To calculate number of unique U.S. visitors to Myspace in July 2015, we need to substitute corresponding value of m into exponential formula. Um = 49.7 * (e^(-0.0671 * 18)) By evaluating this,we can determine answer.
The explicit exponential formula relating the number of months after January 2014 (m) and the number of unique Myspace visitors from the U.S. in that month (Um) can be expressed as follows:
Um = 49.7 * (e^(-0.0671m))
In this formula, Um represents the number of unique visitors from the U.S. in a specific month m after January 2014. The base of the natural logarithm, e, is raised to the power of (-0.0671m), which accounts for the decay in the number of visitors over time. The coefficient 0.0671 determines the rate of decay.
To calculate the number of unique U.S. visitors to Myspace in July 2015, we need to substitute the corresponding value of m into the exponential formula. July 2015 is approximately 18 months after January 2014.
Um = 49.7 * (e^(-0.0671 * 18)) By evaluating this expression, we can determine the number of unique U.S. visitors to Myspace in July 2015.
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Assume that a sample is used to estimate a population proportion p. Find the margin of error M.E. that corresponds to a sample of size 381 with 74% successes at a confidence level of 99.8%. M.E. =% Answer should be obtained without any preliminary rounding. However, the critical value may be rounded to 3 decimal places. Round final answer to one decimal place
The margin of error (M.E.) corresponding to a sample of size 381 with 74% successes at a confidence level of 99.8% is approximately 3.5%.
To find the margin of error (M.E.), we need to consider the sample size, the proportion of successes in the sample, and the confidence level.
Calculate the critical value (z-score) for a 99.8% confidence level:
The confidence level of 99.8% corresponds to a significance level of (1 - 0.998) = 0.002. Since the confidence level is high, we can assume a normal distribution. Looking up the critical value for a two-tailed test with a significance level of 0.002 in the standard normal distribution table, we find a value of approximately 3.09 (rounded to 3 decimal places).
Calculate the standard error (SE):
The standard error measures the variability of sample proportions around the true population proportion. It can be calculated using the formula: SE = sqrt((p * (1 - p)) / n), where p is the sample proportion and n is the sample size. Substituting the values, we have: SE = sqrt((0.74 * 0.26) / 381) ≈ 0.026.
Calculate the margin of error (M.E.):
The margin of error represents the maximum likely difference between the sample proportion and the true population proportion. It can be calculated by multiplying the critical value (z-score) by the standard error. Thus, M.E. = z * SE ≈ 3.09 * 0.026 ≈ 0.08034. Rounded to one decimal place, the margin of error is approximately 0.1 or 3.5%.
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5) A social media research group conducting a study. They wanted to study the sampling distribution of the mean number of hours spent per day on sociai media for college students. They took a sample of 81 students from a larger university and found that the average number of hours was 4:3 hours, and the standard deviation was 1.8 hours per student. Answer the following questions about the sampling distribution of mean. 1) What is the shape of this sampling distribution of mean of number hours spent on social media? 2) What is the mean of the sampling distribution of mean? That is the mean of all means of all samples of size 81. 3) What is the standard deviation of the sampling distribution? 4) Let's suppose one sample of 81 students gave the mean of 5.0 hours per day on social media. Was this an unusual sample - yes or no? 5) If the sample size were 36, what would the standard deviation of the sampling distribution be?
1) Shape of sample mean is bell shaped, it is approximately normal distributed. is the shape of this sampling distribution of mean of number hours spent on social media.
2) 4.3 is the mean of the sampling distribution of mean. That is the mean of all means of all samples of size 81.
3) 0.2 is the standard deviation of the sampling distribution.
4) Let's suppose one sample of 81 students gave the mean of 5.0 hours per day on social media. Since, z score is greater than 2 ,so it is unusual.
5) If the sample size were 36, 0.3 would the standard deviation of the sampling distribution be.
Here, we have,
given
Mean= 4.3
Standard deviation = 1.8
we have,
1)
According to central limit theorem
Shape of sample mean is bell shaped, it is approximately normal distributed.
2)
Mean of sample mean = population mean = 4.3
3)
Standard deviation of sample mean is:
s/√n
=1.8/9
=0.2
According to central limit theorem
Sample mean ~N(u,s/√n )
4)
Mean = 5
Sample mean ~ N(4.3,0.2)
Now ,
Z score for given sample mean = 3.5
Since, z score is greater than 2 ,so it is unusual.
5)
n=36
Standard deviation is:
s/√n
=1.8/6
=0.3
6)
Left tailed test, t test , df =30-1 =29
use excel or t table
Option b is correct.
Excel output is given
p value is 0.020014
Formula used is:
T.DIST(-2.15,30-1,TRUE)
we get,
unusual if z score is |z|>2
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3 12. X'= 2 x²=(²³₁ -¯3) x + (1²) X -1 con X(0) = -0
The given problem involves a first-order nonlinear ordinary differential equation (ODE). We are asked to solve the ODE with an initial condition. The equation is represented as X' = 2x² - (2³₁ - ¯3)x + (1²)x - 1, with the initial condition X(0) = -0.
To solve the given ODE, we can rewrite it as X' = 2x² - (8 - 3)x + (1)x - 1. Simplifying further, we have X' = 2x² - 5x + 1 - 1. This reduces to X' = 2x² - 5x.
To find the solution, we can proceed by separating variables and integrating both sides of the equation. Integrating the left side gives us ∫dX = ∫2x² - 5x dx. Integrating the right side yields X = (2/3)x³ - (5/2)x² + C, where C is the constant of integration.
Applying the initial condition X(0) = -0, we can substitute x = 0 into the equation and solve for C. Since the initial condition implies X(0) = 0, we find C = 0.
Therefore, the solution to the ODE is X = (2/3)x³ - (5/2)x².
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Question 7
I asked in the week one questionnaire how many of you agreed with the following statement "Activities of married women are best confined to the home and family". I received 376 responses to the survey.This is an example of a measure of social conservatism. My research question is: Is there is a difference in the levels of social conservatism between men and women?
Agree Disagree
Female 31 269
Male 7 66
Prefer not to say 0 3
What is the conditional probability that if it is a male that they agree with the statement to 3 significant figures?
1. 0.01892
2. 0.0189
3. 0.0959
4.0.096
The conditional probability that a male agrees with the statement is,
⇒ 0.0959.
Hence option 3 is correct.
To find the conditional probability that a male agrees with the statement, we have to divide the number of male respondents who agree with the statement by the total number of male respondents who answered the question.
From the data you provided, we have,
Number of male respondents who agree with the statement = 7
Total number of male respondents who answered the question = 7+66
= 73
Therefore, the conditional probability that a male agrees with the statement is,
P(Agree|Male) = number of male respondents who agree with the statement / total number of male respondents who answered the question
= 7 / 73
= 0.0959
Hence, the correct option would be 0.0959.
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MARKOV CHAIN:
The Ecuadorian soft drink industry produces two soft drinks: "fructi soda" and "ambateña cola". When a person has bought "fructi soda" there is a 90% chance that he will continue to buy it the next time. If a person bought "ambateña cola", there is an 80% chance that they will repeat the next time, they ask for:
a) if a person is currently a buyer of "Ambateña cola". What is the probability that he will buy "fructi soda" after two purchases from today?
b) if a person is currently a buyer of "fructi soda". What is the probability that he will buy "fructi soda" after three purchases from now?
c) Suppose that 70% of all people today drink "fructi soda" and 30% "ambateña cola". Three purchases from now. What fraction of the shoppers will be drinking "fructi soda"?
d) Determine the equilibrium probability vector.
The equilibrium probability vector is (0.818, 0.182)..P(A3=F|A0=F) = 0.9 × 0.9 × 0.9 = 0.729.
A Markov chain is a stochastic model that is used to study and model random processes. It is a system that transitions from one state to another randomly or in a probabilistic manner.
A state in a Markov chain is a scenario or situation that the system can exist in. In this case, the two states are "fructi soda" and "ambateña cola".If a person is currently a buyer of "Ambateña cola".
What is the probability that he will buy "fructi soda" after two purchases from today?The transition probability matrix is given below:After one purchase, if a person buys "fructi soda", there is a 0.9 probability that they will repeat it for the next purchase.
If a person buys "ambateña cola", there is an 0.8 probability that they will repeat it for the next purchase.Using the transition matrix, the probability that a person will buy "fructi soda" after two purchases given that they currently buy "ambateña cola" is given by:P(A2=F|A0=A) = P(A2=F|A1=A) × P(A1=A|A0=A)P(A2=F|A1=A) = 0.9 (from the transition matrix)P(A1=A|A0=A) = 0.2 (the person has bought "ambateña cola").
Hence:P(A2=F|A0=A) = 0.9 × 0.2 = 0.18.Therefore, the probability that a person who currently buys "ambateña cola" will buy "fructi soda" after two purchases is 0.18.
If a person is currently a buyer of "fructi soda". What is the probability that he will buy "fructi soda" after three purchases from now?P(A3=F|A0=F) = P(A3=F|A2=F) × P(A2=F|A1=F) × P(A1=F|A0=F)P(A2=F|A1=F) = 0.9 (from the transition matrix)P(A3=F|A2=F) = 0.9 (from the transition matrix)P(A1=F|A0=F) = 0.9 (the person has bought "fructi soda")
Hence:P(A3=F|A0=F) = 0.9 × 0.9 × 0.9 = 0.729.Therefore, the probability that a person who currently buys "fructi soda" will buy "fructi soda" after three purchases is 0.729.
Suppose that 70% of all people today drink "fructi soda" and 30% "ambateña cola".
Three purchases from now. What fraction of the shoppers will be drinking "fructi soda"?Let F3 and A3 be the fraction of people drinking "fructi soda" and "ambateña cola" respectively after three purchases from now.
Then we have:F3 = 0.9F2 + 0.2A2A3 = 0.1F2 + 0.8A2F2 = 0.9F1 + 0.2A1A2 = 0.1F1 + 0.8A1F1 = 0.9F0 + 0.2A0A1 = 0.1F0 + 0.8A0We know that 70% of all people drink "fructi soda" and 30% "ambateña cola".
Therefore, we can write:F0 = 0.7 and A0 = 0.3Solving the above equations for F3, we get:F3 = 0.756.
This means that after three purchases, approximately 75.6% of the shoppers will be drinking "fructi soda".d) Determine the equilibrium probability vector.
The equilibrium probability vector is a probability vector that remains unchanged after a transition. It can be found by solving the system of equations given by:πP = πwhere π is the probability vector and P is the transition matrix.πF + πA = 1 (the sum of the probabilities is equal to 1)0.9πF + 0.2πA = πF0.1πF + 0.8πA = πA
Solving these equations, we get:πF = 0.818πA = 0.182.
Therefore, the equilibrium probability vector is (0.818, 0.182)..
In conclusion, the following results are obtained from the calculations done:If a person is currently a buyer of "Ambateña cola", the probability that he will buy "fructi soda" after two purchases from today is 0.18. If a person is currently a buyer of "fructi soda", the probability that he will buy "fructi soda" after three purchases from now is 0.729. After three purchases from now, approximately 75.6% of the shoppers will be drinking "fructi soda". The equilibrium probability vector is (0.818, 0.182).
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find a general solution for the differential equation with x as the independent variable. 1. y" + 2y" - 8y' = 0 2. y"" - 3y" - y' + 3y = 0 3. 62"" +72"-2²-22=0 4. y"" + 2y" 19y' - 20y = 0 5. y"" + 3y" +28y' +26y=0 6. y""y"+ 2y = 0 7. 2y""y" - 10y' - 7y=0 8. y"" + 5y" - 13y' + 7y=0
1. y" + 2y' - 8y = 0Solution:Here, the auxiliary equation is m²+2m-8 =0.Solving it, we get (m-2)(m+4) = 0
∴ m=2, -4
∴ y = c1e^(2x)+c2e^(-4x) is the general solution.
2. y" - 3y" - y' + 3y = 0
Solution:Here, the auxiliary equation is m²-3m-m+3 = 0.
∴ (m-3)(m+1) -0
∴ m=3, -1
∴ y = c1e^(3x)+c2e^(-x) is the general solution.3.
62" +72" - 22² -22 = 0
Solution:Here, the auxiliary equation is 6²m+7²m-22 = 0.∴ 36m² + 49m² -22 = 0.∴ 85m² -22 = 0.
∴ m = 2/5, -2/17
∴ y = c1e^2/5x + c2e^(-2/17x) is the general solution.4.
y" + 2y" 19y' - 20y = 0
Solution:Here, the auxiliary equation is m²+2m-20m=0.
∴ (m+5)(m-4) = 0.
∴ m = -5, 4.
∴ y = c1e^(-5x) + c2e^(4x) is the general solution.
5. y" + 3y" +28y' +26y=0
Solution:Here, the auxiliary equation is m²+3m+28m+26 = 0.
∴ m²+31m+26 = 0.
∴ m = (-31±√965)/2.
∴ y = c1e^(-31+√965)/2x + c2e^(-31-√965)/2x is the general solution.6.
y"y" + 2y = 0
Solution:Here, the auxiliary equation is m²+2 = 0.
∴ m = ±i.
∴ y = c1cos(x) + c2sin(x) is the general solution.7.
2y"y" - 10y' - 7y=0
Solution:Here, the auxiliary equation is 2m²-10m-7=0.
∴ m = (10±√156)/4.
∴ y = c1e^(5+√7)/2x + c2e^(5-√7)/2x is the general solution.8.
y" + 5y" - 13y' + 7y=0
Solution:Here, the auxiliary equation is m²+5m-13m+7=0.
∴ m²-8m+7=0.
∴ m = 4±√9.
∴ y = c1e^(4+√9)x + c2e^(4-√9)x is the general solution.
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draw the line for slope and slope of the line
The slope of the line in this problem is given as follows:
m = 2.
How to define a linear function?The slope-intercept equation for a linear function is presented as follows:
y = mx + b
In which:
m is the slope.b is the intercept.Two points on the equation of the line in this problem are given as follows:
(0, -8) and (9, 10).
Hence the rise and the run are given as follows:
Rise: 10 - (-8) = 18.Run: 9 - 0 = 9.Then the slope is given as follows:
m = Rise/Run
m = 18/9
m = 2.
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A random sample of 40 observations is to be drawn from a large population of measurements. It is known that 30% of the measurements in the population are 1's, 20% are 2's, 20% are 3's and 30% are 4's.
a) Give the mean and standard deviation of the (repeated) sampling distribution of x, the sample mean of the 40 observations.
b) Describe the shape of the sampling distribution of . Does the answer depend on sample size?
a) The mean and standard deviation of the sampling of x can be determined as follows : Mean μx = Σx/n where Σx is the total of all 40 observations and n = 40 is the sample size.
The probability distribution of the population is not required for this calculation. The sum of the probabilities of all possible events is always 1. Therefore, the sum of the population proportions should be 1:30% + 20% + 20% + 30% = 100% = 1In order to determine the value of Σx for the population, the following formula may be used:Σx = (0.3)(1) + (0.2)(2) + (0.2)(3) + (0.3)(4) = 2.7So, the mean of the sampling distribution is:μx = Σx/n = 2.7/40 = 0.0675Similarly, the standard deviation of the sampling distribution is:σx = sqrt [ Σ ( xi - μx )2 / n ] = sqrt [ Σ (pi) (xi - μx)2 ] = sqrt (0.0129) = 0.1135Therefore, the mean of the sampling distribution is 0.0675 and the standard deviation is 0.1135. b) The shape of the sampling distribution of x is normal. This result is a consequence of the central limit theorem. According to the central limit theorem, when the sample size is sufficiently large, regardless of the shape of the population, the distribution of the sample means will follow an approximately normal distribution.
Hence, in this case, since the sample size is 40 which is greater than 30, the sampling distribution of x is normally distributed. The answer does not depend on sample size.
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Solve the system: 3x−5y=a
5x−7y=b
where (i) a=0,b=0 and (ii) a=2,b=6 What is the solution of only the first equation in (i) and (ii), and what is the solution of the second equation in (i) and (ii)?
Given system of equations are:
3x-5y = a --- (1)
5x - 7y = b --- (2)
(i) a = 0, b = 0
Substituting the given values in the above equations, we get
3x - 5y = 0 --- (1)
5x - 7y = 0 --- (2)
Now, let's solve the equations to get the solutions:
For equation 1:
3x - 5y = 0
⇒ 3x = 5y
keeping x on the other side by dividing the entire equation by 3
⇒ x = (5/3)y
So, the solution of the first equation is x = (5/3)y
For equation 2:
5x - 7y = 0
⇒ 5x = 7y
keeping x on the other side by dividing the entire equation by 5
⇒ x = (7/5)y
So, the solution of the second equation is x = (7/5)y
(ii) a = 2, b = 6
Substituting the given values in the above equations, we get
3x - 5y = 2 --- (1)
5x - 7y = 6 --- (2)
Now, let's solve the equations to get the solutions:
For equation 1:
3x - 5y = 2
⇒ 3x = 5y + 2
keeping x on the other side by dividing the entire equation with 3
⇒ x = (5/3)y + (2/3)
So, the solution of the first equation is x = (5/3)y + (2/3)
For equation 2:
5x - 7y = 6
⇒ 5x = 7y + 6
keeping x on the other side by dividing the entire equation by 5
⇒ x = (7/5)y + (6/5)
So, the solution of the second equation is x = (7/5)y + (6/5)
Hence, the solutions of the first equation in (i) and (ii) are: x = (5/3)y and x = (5/3)y + (2/3) respectively.
And the solutions of the second equation in (i) and (ii) are: x = (7/5)y and x = (7/5)y + (6/5) respectively.
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The Wellington company wants to develop a simple linear regression model for one of its products. Use the following 12 periods of historical data to develop the regression equation and use it to forecast the next three periods.
The simple linear regression line is ??????????? (Enter your responses rounded to two decimal places and include a minus sign if necessary.)
Find the forecasts for periods 13-15 based on the simple linear regression and fill in the table below (enter your responses rounded to two decimal places).
Period (x) Forecast (Ft)
13 14 15
The simple linear regression line is 973.65 + ( -45.16 )[tex]x_{1}[/tex]
Forecast 13 = 386.57
Forecast 14 = 341.41
Forecast 15 = 296.25
Given,
12 periods of historical data.
Now,
According to simple regression line standard form,
y = mx + b
y = response (dependent) variable
x = predictor (independent) variable
m = estimated slope
b = estimated intercept.
So here the the regression line equation will be
973.65 + (-45.16)[tex]x_{1}[/tex]
Forecast 13
Substitute the value of [tex]x_{1}[/tex]
Forecast 13 = 973.65 + (-45.16)13
Forecast 13 = 386.57
Forecast 14
Substitute the value of [tex]x_{1}[/tex]
Forecast 14 = 973.65 + (-45.16)14
Forecast 14 = 341.41
Forecast 15
Substitute the value of [tex]x_{1}[/tex]
Forecast 15 = 973.65 + (-45.16)15
Forecast 15 = 296.25
Thus the regression line equations and forecast can be calculated .
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5 pointsIn a city,about 45% of all residents have received a COVID-19 vaccine.Suppose that a random sample of 12 residents is selected Part A Calculate the probability that exactly 4 residents have received a COVID-19 vaccine in the sample. (Round the probabilities to 4 decimal places if possible Part B
Calculate the probability that at most 4 residents have received a COVID-19 vaccine in the sample (Round the probabilities to 4 decimal places if possible)
In a city, about 45% of all residents have received a COVID-19 vaccine.
A random sample of 12 residents is selected. We are to calculate the probability that exactly 4 residents have received a COVID-19 vaccine in the sample and the probability that at most 4 residents have received a COVID-19 vaccine in the sample.
Part AThe given problem represents a binomial probability distribution.
The binomial probability function is given as[tex];$$P(x) = \binom{n}{x}p^x(1-p)^{n-x}$$[/tex]where x is the number of successes, n is the number of trials, p is the probability of success in each trial, and 1 - p is the probability of failure in each trial.
[tex]In the given problem, the probability of success (p) is 0.45, n is 12, and x is 4.P(4) is given as, $$P(4) = \binom{12}{4}(0.45)^4(1-0.45)^{12-4}$$Therefore, $$P(4) = \binom{12}{4}(0.45)^4(0.55)^8 = 0.1797$$[/tex]
[tex]is 0.45, n is 12, and x is 4.P(4) is given as, $$P(4) = \binom{12}{4}(0.45)^4(1-0.45)^{12-4}$$Therefore, $$P(4) = \binom{12}{4}(0.45)^4(0.55)^8 = 0.1797$$[/tex]
Thus, the probability that exactly 4 residents have received a COVID-19 vaccine in the sample is 0.1797.
Part B The probability of at most 4 residents receiving a COVID-19 vaccine in the sample can be given by;$$P(X \leq 4) = P(X=0) + P(X=1) + P(X=2) + P(X=3) + P(X=4)$$
[tex]$$P(X \leq 4) = P(X=0) + P(X=1) + P(X=2) + P(X=3) + P(X=4)$$[/tex]
Now, we need to calculate the individual probabilities of [tex]$P(X=0)$, $P(X=1)$, $P(X=2)$, $P(X=3)$, and $P(X=4)$.[/tex]
W[tex]e can use the binomial probability function to calculate the probabilities. P(X=0), $$P(X=0) = \binom{12}{0}(0.45)^0(0.55)^{12} = 0.000303$$P(X=1),$$P(X=1) = \binom{12}{1}(0.45)^1(0.55)^{11} = 0.00352$$P(X=2),$$P(X=2) = \binom{12}{2}(0.45)^2(0.55)^{10} = 0.01923$$P(X=3),$$P(X=3) = \binom{12}{3}(0.45)^3(0.55)^{9} = 0.06443$$P(X=4),$$P(X=4) = \binom{12}{4}(0.45)^4(0.55)^{8} = 0.1797$$Therefore, $$P(X \leq 4) = 0.000303 + 0.00352 + 0.01923 + 0.06443 + 0.1797$$$$P(X \leq 4) = 0.2671$$\pi[/tex]
Thus, the probability that at most 4 residents have received a COVID-19 vaccine in the sample is 0.2671.
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these selected numbers are the resul of the nomal selection procedure used for every drwing, the distrbution of the selected numbers is a normal dathbution? What is tho chape of the distribeiton of thoses welected numbers? Wil A be a normal detributco? Chacse the right arsiser. A. The distribubon will be rectangularshaped and nol a normat ditributon, 8. The disiributon we be cecular-shaped and not a normal distribution: C. The devibution wit be bell-shaped but not a normal distrbution. D. The datribution will be bel-shaped and n is a normal distributon
Option D is correct, distribution will be bell-shaped and is not a normal distribution.
The distribution will be bell-shaped and is not a normal distribution.
The reason is that the selected numbers are the result of a normal selection procedure, which implies that they follow a normal distribution. The normal distribution is well-known for its bell-shaped curve.
Therefore, the distribution of the selected numbers will also be bell-shaped.
However, it's important to note that being bell-shaped does not necessarily mean that the distribution is a normal distribution.
The normal distribution has specific characteristics, such as a symmetric bell-shaped curve and specific mean and standard deviation values.
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Translating research questions into hypotheses. Translate each of the following research questions into appropriate H_{0} and H_{a}
a. U.S. Census Bureau data show that the mean household income in the area served by a shopping mall is $78,800 per year. A market research firm questions shoppers at the mall to find out whether the mean household income of mall shoppers is higher than that of the general population.
b. Last year, your online registration technicians took an average of 0.4 hour to respond to trouble calls from students trying to register. Do this year's data show a different average response time?
c. In 2019, Netflix's vice president of original content stated that the average Netflix subscriber spends two hours a day on the service.15 Because of an increase in competing services, you believe this average has declined this year.
In order to conduct effective research, it is important to translate research questions into appropriate hypotheses. Hypotheses provide a clear and testable statement of what the researcher believes to be true about the population being studied.
For the first research question, the null hypothesis states that the mean household income of mall shoppers is not higher than that of the general population, while the alternative hypothesis suggests that the mean household income of mall shoppers is higher than that of the general population.
This allows the market research firm to investigate whether mall shoppers have a higher income level than the general population.
The second research question compares last year's average response time for online registration technicians with this year's data. The null hypothesis states that the average response time this year is the same as last year, while the alternative hypothesis suggests that the average response time this year is different from last year.
This enables the organization to determine if there has been any change in the performance of their technicians.
Finally, the third research question investigates if Netflix subscribers' average time spent on the service per day has declined this year. The null hypothesis states that the average time spent has not declined, while the alternative hypothesis suggests that it has.
This provides insight into how competing services may be impacting Netflix's user engagement.
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If we like to test
H0: Variance of electronic = Variance of utilities
H1: Variance of electronic ≠ Variance of utilities
Which one is the correct one?
a. We need to do Shapiro test with log transformed data.
b. Since we do not assume that both data are from a normal distribution, we need to do Shapiro test first to see that data are from a normal distribution.
c. We can do F test right away.
d. We need to do F test with log transform data.
If the F statistic is less than the critical value, we fail to reject the null hypothesis and conclude that the variances are equal.So, the correct answer is c.
An F-test is a statistical test used to compare the variances of two or more samples.
It is used to compare whether the variances of two groups are similar or different, or whether the variances of multiple groups are equal or different.
In ANOVA, the F-test is used to determine whether there is a significant difference between the means of two or more groups. It is also used to test for the significance of regression models.In this case, we need to test the following hypotheses:H0:
Variance of electronic = Variance of utilitiesH1:
Variance of electronic ≠ Variance of utilitiesFor this case, we can perform an F-test right away to determine whether the variances are equal or not.
The F-test for equality of variances is a one-tailed test.
It is calculated as the ratio of the variances of two samples.
The F statistic is calculated by dividing the variance of the sample with the larger variance by the variance of the sample with the smaller variance.
If the F statistic is greater than the critical value, we can reject the null hypothesis and conclude that the variances are not equal.
If the F statistic is less than the critical value, we fail to reject the null hypothesis and conclude that the variances are equal.So, the correct answer is c. We can do F test right away.
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An all-women's college is interested in whether it places more females in male-dominated careers (e.g., engineering, physical science) than is reflected in the national data for career placement. According to some statistics from the National Center for Educational Statistics, only around 22% of people in engineering and physical science jobs were females in the 1990s (see Bona, Kelly & Jung, 2011, who published about this topic in the Psi Chi journal, if you are interested in this topic). For this problem, assume that figure has remained constant over time. You examine your alumni data, which simply includes annual averages over the past 20 years, (N = 20), and find that on average, 23.7% of graduates have been placed in such occupations, with a standard deviation of 6.1%.
(a) Test your hypothesis as a two-tailed test with alpha = .05.
(b) Compute the 95% confidence interval. Do the results from your confidence interval agree with your decision from the hypothesis test? Explain.
(c) Compute the effect size for this analysis and interpret it.
The analysis of an all-women's college alumni data suggests that the proportion of females placed in male-dominated careers is moderately different from the national average, with no statistical significance found.
(a) To test the hypothesis, we can use a two-tailed test with alpha = .05. Our null hypothesis (H0) is that the proportion of females placed in male-dominated careers is equal to the national average of 22%. The alternative hypothesis (Ha) is that the proportion differs from 22%. Using a z-test for proportions, we calculate the test statistic: z = (0.237 - 0.22) / sqrt[(0.22 * (1 - 0.22)) / 20] = 0.017 / 0.0537 ≈ 0.316. With a two-tailed test, the critical z-value for alpha = .05 is ±1.96. Since |0.316| < 1.96, we fail to reject the null hypothesis.
(b) To compute the 95% confidence interval, we use the formula: CI =p± (z * sqrt[(p * (1 - p)) / n]). Plugging in the values, we get CI = 0.237 ± (1.96 * sqrt[(0.237 * (1 - 0.237)) / 20]) ≈ 0.237 ± 0.096. Thus, the confidence interval is approximately (0.141, 0.333). As the interval includes the national average of 22%, the results from the confidence interval agree with the decision from the hypothesis test.
(c) To compute the effect size, we can use Cohen's h. Cohen's h = 2 * arcsine(sqrt(p)) ≈ 2 * arcsine(sqrt(0.237)) ≈ 0.499. The interpretation of the effect size depends on the context, but generally, an h value around 0.5 suggests a moderate effect. This means that the proportion of females placed in male-dominated careers at the all-women's college is moderately different from the national average.Therefore, The analysis of an all-women's college alumni data suggests that the proportion of females placed in male-dominated careers is moderately different from the national average, with no statistical significance found.
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The piston diameter of a certain hand pump is
0.4
inch. The manager determines that the diameters are normally distributed, with a mean of
0.4
inch and a standard deviation of
0.006
inch. After recalibrating the production machine, the manager randomly selects
27
pistons and determines that the standard deviation is
0.0054
inch. Is there significant evidence for the manager to conclude that the standard deviation has decreased at the
α=0.10
level of significance?
Question content area bottom
Part 1
What are the correct hypotheses for this test?
The null hypothesis is
H0:
▼
sigmaσ
pp
muμ
▼
greater than>
not equals≠
equals=
less than<
▼
0.006.
0.0054.
The alternative hypothesis is
H1:
▼
pp
muμ
sigmaσ
▼
less than<
not equals≠
equals=
greater than>
▼
0.0054.
0.006.
The correct hypotheses for this test are:
Null hypothesis (H0):
H0: σ = 0.006
Alternative hypothesis (H1):
H1: σ < 0.006
We have,
In hypothesis testing, we set up the null hypothesis (H0) as the statement we want to test against, and the alternative hypothesis (H1) represents the alternative possibility we consider if there is evidence against the null hypothesis.
In this case, the null hypothesis is that the standard deviation (σ) of the piston diameter remains at 0.006 inches.
The null hypothesis assumes that there is no change or improvement in the standard deviation after recalibrating the production machine.
The alternative hypothesis is that the standard deviation has decreased and is less than 0.006 inches.
The alternative hypothesis suggests that the recalibration of the production machine has led to a decrease in the variability of the piston diameter.
By testing these hypotheses, we can determine if there is significant evidence to support the claim that the standard deviation has decreased, indicating an improvement in the manufacturing process.
Thus,
Null hypothesis (H0):
H0: σ = 0.006
Alternative hypothesis (H1):
H1: σ < 0.006
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An English teacher was interested in studying the length of words in Shakespeare's MacBeth. She took a random sample of 300 words from MacBeth and wrote down the length of each word. She found that the average lexigth of words in that sample was 3.4 letters. What would be the parameter? a. number of words in the sample b. 3.4 c. average number of letters per word in the entire play of MacBeth d. all words in the play
Option C) average number of letters per word in the entire play of MacBeth.
In statistical terms, a parameter refers to a numerical characteristic of a population. As a result, we can classify parameters as population-based statistics. When a sample is taken from the population and statistical values are measured for the samples, they are referred to as statistics.
An English teacher wanted to investigate the length of words in Shakespeare's MacBeth. She gathered a random sample of 300 words from MacBeth and recorded the length of each word.
She discovered that the average word length in that sample was 3.4 letters long. As a result, the parameter would be the average number of letters per word in the entire play of MacBeth.
This means that we would need to calculate the average length of all words in the play to find the population's mean length of words.
Hence, the correct option is c. average number of letters per word in the entire play of MacBeth.
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4. (10pts - Normal Approximation to Binomial Theorem) Suppose that 75% of registered voters voted in their most recent local election. What is the probability that in a sample of 500 registered voters that at least 370 voted in their most recent local election?
To find the probability that at least 370 out of 500 registered voters voted in their most recent local election, we can use the normal approximation to the binomial distribution.
Given that the proportion of registered voters who voted is 75% and the sample size is 500, we can calculate the mean and standard deviation of the binomial distribution. The mean (μ) is equal to np, where n is the sample size and p is the proportion of success. In this case, μ = 500 * 0.75 = 375. The standard deviation (σ) is equal to sqrt(np(1-p)). Here, σ = sqrt(500 * 0.75 * (1-0.75)) ≈ 9.61.
To find the probability of at least 370 voters, we need to calculate the z-score corresponding to 370 and then find the probability of obtaining a z-score greater than or equal to that value. The z-score is calculated as (x - μ) / σ, where x is the number of voters.
Using the z-score formula, the z-score is (370 - 375) / 9.61 ≈ -0.52. We then find the probability of obtaining a z-score greater than or equal to -0.52 using a standard normal distribution table or a calculator. The probability is approximately 0.7006.
Therefore, the probability that at least 370 out of 500 registered voters voted in their most recent local election is approximately 0.7006, or 70.06%.
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Let z = z(x, y) be an implicit function defined by the equation x^3 + 3(y^2)z − xyz^3 = 0. Find ∂z/∂x and ∂z/∂y .
The partial derivatives ∂z/∂x and ∂z/∂y of the implicit function z = z(x, y) defined by the equation x^3 + 3(y^2)z − xyz^3 = 0 are given by ∂z/∂x = (yz^3 - 3x^2) / (3(y^2) - 3xz^2) and ∂z/∂y = (xz^3 - 6yz) / (3(y^2) - 3xz^2), respectively.
To find the partial derivative ∂z/∂x, we differentiate the equation x^3 + 3(y^2)z − xyz^3 = 0 with respect to x, treating z as a function of x and y. Rearranging the terms and solving for (∂z/∂x), we obtain ∂z/∂x = (yz^3 - 3x^2) / (3(y^2) - 3xz^2).
Similarly, to find the partial derivative ∂z/∂y, we differentiate the equation with respect to y, treating z as a function of x and y. Rearranging the terms and solving for (∂z/∂y), we obtain ∂z/∂y = (xz^3 - 6yz) / (3(y^2) - 3xz^2).
Therefore, the partial derivatives are ∂z/∂x = (yz^3 - 3x^2) / (3(y^2) - 3xz^2) and ∂z/∂y = (xz^3 - 6yz) / (3(y^2) - 3xz^2).
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An article in the Son jose Mercury News stated that students in the California state university system take 6 years, on average, to finish their undergraduate degrees. A freshman student believes that the mean time is less and conducts a survey of 38 students. The student obtains a sample mean of 5.6 with a sample standard deviation of 0.9. Is there sufficient evidence to support the student's claim at an α=0.1 significance level? Preliminary: a. Is it safe to assume that n≤5% of all college students in the local area? No Yes b. 15n≥30? Yes. No Test the claim: a. Determine the null and alternative hypotheses, Enter correct symbol and value. H 0
:μ=
H a
:μ
b. Determine the test statistic. Round to four decimal places. t= c. Find the p-value. Round to 4 decimals. p-value = d. Make a decision. Fail to reject the null hypothesis. Reject the null hypothesis. e. Write the conclusion. There is sufficient evidence to support the claim that the mean time to complete an undergraduate degree in the California state university system is less than 6 years. There is not sufficient evidence to support the claim that that the mean time to complete an undergraduate degree in the California state university system is less than 6 years.
No Test the claim Determine the null and alternative hypotheses, Enter correct symbol and value. H0:μ=6H1:μ<6b. Determine the test statistic. Round to four decimal places.
t=(x¯−μ)/(s/√n)
=(5.6-6)/(0.9/√38)
= -2.84c.
Find the p-value. Round to 4 decimals. We will use the t-distribution with degrees of freedom There is sufficient evidence to support the claim that the mean time to complete an undergraduate degree in the California state university system is less than 6 years.
df = n-1
= 38 - 1
= 37.
The area to the left of -2.84 is 0.0049. Hence, the P-value is P(t < -2.84) = 0.0049d. Make a decision. Fail to reject the null hypothesis. Reject the null hypothesise. Write the conclusion. There is sufficient evidence to support the claim that the mean time to complete an undergraduate degree in the California state university system is less than 6 years.
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Biologists are treating a lake contaminated with bacteria. The level of contamination is changing at a rate of day, where is the number of days since treatment began. Find a function N() to estimate the level of contamination if the level after 1 day was 5730 bacteria per cubic centimeter.
The level of contamination after 1 day was 5730 bacteria per cubic centimeter, the function N(t) can be written as N(t) = N₀ * e^(-kt), where N₀ represents the initial level of contamination and k is the decay constant.
To estimate the level of contamination in the lake, an exponential decay model is commonly used. In this case, the function N(t) represents the level of contamination at time t, and it can be expressed as N(t) = N₀ * e^(-kt). The value of N₀ is the initial level of contamination, and k represents the decay constant.
Given that the level of contamination after 1 day was 5730 bacteria per cubic centimeter, we can substitute the values into the exponential decay model equation:
5730 = N₀ * e^(-k * 1).
To determine the function N(t) and estimate the level of contamination at any given time, we would need more information, such as the decay rate of the contamination or additional data points to solve for the values of N₀ and k.
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A coin-operated drink machine was designed to discharge a mean of 6 fuld ounces of coffee per cup. In a test of the machine, the charge atsi31 randomly chosen cups of coffee from the machine were recorded. The sample mean and sample standard deviation were 6.13 fuid ounces and 0.31 ounces, respectively If we assume that the discharge amounts are approximately normally distributed, is there enough evidence, to conclude that the pripulation mean discharge, differs from 6 fluid ounces? Use the 0.05 level of significance. Perform a two-tailed test. Then complete the parts below. Carry your intermediate computations to three or more decimal places. (If necessary, consulta list of formulas) (a) State the null hypothesis , and the alternative hypothesis 10 (b) Determine the type of test statistic to use.
In this hypothesis test, the null hypothesis states that the population mean discharge is equal to 6 fluid ounces, while the alternative hypothesis suggests that the population mean discharge differs from 6 fluid ounces.
To test this, we will use a two-tailed test at a significance level of 0.05.
(a) The null hypothesis (H0) and the alternative hypothesis (Ha) can be stated as follows:
Null hypothesis (H0): The population mean discharge is equal to 6 fluid ounces.
Alternative hypothesis (Ha): The population mean discharge differs from 6 fluid ounces.
(b) To test these hypotheses, we will use a two-tailed test because the alternative hypothesis does not specify whether the population mean discharge is greater or smaller than 6 fluid ounces. We want to determine if there is evidence to conclude that the population mean discharge is different from 6 fluid ounces.
To perform the hypothesis test, we need to calculate the test statistic. In this case, since the sample size is large (n > 30) and the population standard deviation is unknown, we will use the t-test statistic. The formula for the t-test statistic is:
t = (sample mean - population mean) / (sample standard deviation / √n)
where t follows a t-distribution with (n - 1) degrees of freedom. We will compare the calculated t-value with the critical t-value from the t-distribution table, considering a two-tailed test at a significance level of 0.05. If the calculated t-value falls outside the critical region, we can reject the null hypothesis and conclude that the population mean discharge differs from 6 fluid ounces.
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Express the ratio below in its simplest form
12:6
Answer:
12/6 simplified to lowest terms is 2/1.
Step-by-step explanation:
Divide both the numerator and denominator by the HCF
12 ÷ 6
6 ÷ 6
Reduced fraction:
12/6 simplified to lowest terms is 2/1.
Answer: 2:1
Step-by-step explanation:
12:6
Both left and right can be divided by 6, like a fraction, reduce.
= 2:1
QUESTION 5
It s knovm that mean age of me population ot n same community 51 years. What s the expected valuen of the sampling distibutm of the sanple mean? Round your answer to the nunber of years
QUESTION 6
If me proporton of Mutercard tansactms in a of various credit card transactions iS ecuaj to 0.276 and samoe size iS n. wtat iS the margin ot error for the corresoonding 94% wmnoence Reval to estmate the
propotion of Mastercard transactons in the population? Assume that me conditions for the sampling distribution to be approximately normal are satisfied. Use Excel to calculate and round your answer to 4 decimals.
5. The mean age of the population of doctors is known to be 53 years, so the expected value of the sampling distribution of the sample mean is also 53 years.
6. The left boundary of the confidence interval is 57.13.
5. To find the left boundary of the confidence interval to estimate the population mean, we need to subtract the margin of error from the sample mean.
Left boundary = Sample mean - Margin of error
Given:
Sample mean = 62.66
Margin of error = 5.53
6. Calculating the left boundary:
Left boundary = 62.66 - 5.53 = 57.13
Therefore, the left boundary of the confidence interval to estimate the population mean is 57.13.
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The complete question is below:
It s known that the mean age of the populaiton of doctors in some community is 53 years. What is the expected value of the sampling distribution of the sample mean? Round your answer to the whole number of years. QUESTION 6 Given a sample mean 62.66 and a margin of error 5.53, what is the left boundary of the confidence interval to estimate the population mean? Round your answer to 2 decimal places.
Oxnard Petro, Ltd., has three interdisciplinary project development teams that function on an ongoing basis. Team members rotate from time to time. Every 4 months (three times a year) each department head rates the performance of each project team (using a 0 to 100 scale, where 100 is the best rating). Are the main effects significant? Is there an interaction?
Year Department
Marketing Engineering Finance
2004 90 69 96
84 72 86
80 78 86
2005 72 73 89
83 77 87
82 81 93
2006 92 84 91
87 75 85
87 80 78
Choose the correct row-effect hypotheses.
a. H0: A1 ≠ A2 ≠ A3 ≠ 0 H1: All the Aj are equal to zero
b. H0: A1 = A2 = A3 = 0 H1: Not all the Aj are equal to zero
(a-2) Choose the correct column-effect hypotheses.
a. H0: B1 ≠ B2 ≠ B3 ≠ 0 H1: All the Bj are equal to zero
b. H0: B1 = B2 = B3 = 0 H1: Not all the Bj are equal to zero
(a-3) Choose the correct interaction-effect hypotheses.
a. H0: Not all the ABjk are equal to zero H1: All the ABjk are equal to zero
b. H0: All the ABjk are equal to zero H1: Not all the ABjk are equal to zero
The row-effect hypotheses compare department means, the column-effect hypotheses compare year means, and the interaction-effect hypotheses examine interaction effects.
To determine the main effects and interaction in the given data, we can perform a two-way analysis of variance (ANOVA). The row effect corresponds to the three departments (Marketing, Engineering, Finance), the column effect corresponds to the three years (2004, 2005, 2006), and the interaction effect tests whether the combined effect of department and year is significant.The correct row-effect hypotheses are:
a- H0: A1 ≠ A2 ≠ A3 ≠ 0 (Null hypothesis: the means of the departments are not all equal)b- H1: All the Aj are equal to zero (Alternative hypothesis: the means of the departments are all equal)
The correct column-effect hypotheses are:b- H0: B1 = B2 = B3 = 0 (Null hypothesis: the means of the years are all equal)
a- H1: Not all the Bj are equal to zero (Alternative hypothesis: the means of the years are not all equal)The correct interaction-effect hypotheses are:
b- H0: All the ABjk are equal to zero (Null hypothesis: there is no interaction effect)a- H1: Not all the ABjk are equal to zero (Alternative hypothesis: there is an interaction effect)
To determine if the main effects and interaction are significant, we would need to perform the ANOVA calculations using statistical software or tables and compare the obtained p-values with a chosen significance level (e.g., α = 0.05).
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For the specific utility function given, find MRS in general terms (no numbers).
The Marginal Rate of Substitution (MRS) measures the rate at which a consumer is willing to trade one good for another while keeping utility constant. In general terms, the MRS can be determined by taking the ratio of the marginal utility of one good to the marginal utility of the other.
The Marginal Rate of Substitution (MRS) is a concept used in microeconomics to analyze consumer behavior and preferences. It quantifies the amount of one good a consumer is willing to give up in exchange for another, while maintaining the same level of satisfaction or utility.
To find the MRS in general terms, we can consider a specific utility function and differentiate it with respect to the quantities of the two goods. Let's assume the utility function is U(x, y), where x represents the quantity of one good and y represents the quantity of another. The MRS can be calculated as the ratio of the marginal utility of good x (MUx) to the marginal utility of good y (MUy): MRS = MUx/MUy.
The marginal utility represents the additional utility derived from consuming an additional unit of a good. By calculating the derivatives of the utility function with respect to x and y, we can obtain the marginal utilities. The MRS formula allows us to understand how the consumer values the goods relative to each other and how they are willing to trade off one good for another while maintaining constant satisfaction.
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the question is " find the radious and interval of convergence of
the following series,
can you make this question on paper and step by step please ?
The radius and interval of convergence of the given series [tex]\sum_{k=1}^\infty[/tex] (x - 2)ᵏ . 4ᵏ are 0.25 and (1.75, 2.25) respectively.
Given the series is (x - 2)ᵏ . 4ᵏ
So the k th term is = aₖ = (x - 2)ᵏ . 4ᵏ
The k th term is = aₖ₊₁ = (x - 2)ᵏ⁺¹ . 4ᵏ⁺¹
So now, | aₖ₊₁/aₖ | = | [(x - 2)ᵏ⁺¹ . 4ᵏ⁺¹]/[(x - 2)ᵏ . 4ᵏ] | = | 4 (x - 2) |
Since the series is convergent then,
| aₖ₊₁/aₖ | < 1
| 4 (x - 2) | < 1
- 1 < 4 (x - 2) < 1
- 1/4 < x - 2 < 1/4
- 0.25 < x - 2 < 0.25
2 - 0.25 < x - 2 + 2 < 2 + 0.25 [Adding 2 with all sides]
1.75 < x < 2.25
So, the radius of convergence = 1/4 = 0.25
and the interval of convergence is (1.75, 2.25).
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Complete question is below
find the radius and interval of convergence of the following series
[tex]\sum_{k=1}^\infty[/tex] (x - 2)ᵏ . 4ᵏ
Determine the PA factor value for i 7.75% and n 10
years, using the three methods described previously.
The PA factor values for an interest rate of 7.75% and a number of periods of 10 years
1. Discrete Compounding (Annual): PA = 1.935047075
2. Continuous Compounding: PA = 2.399857382
3. Discrete Compounding (Semi-Annual): PA = 1.954083502
To determine the PA factor value for an interest rate (i) of 7.75% and a number of periods (n) of 10 years using the three methods, we can calculate it using the formulas for each method:
1. Discrete Compounding (Annual):
PA = (1 + i)^n
PA = (1 + 0.0775)^10 = 1.935047075
2. Continuous Compounding:
PA = e^(i*n)
PA = e^(0.0775*10) = 2.399857382
3. Discrete Compounding (Semi-Annual):
PA = (1 + i/2)^(2*n)
PA = (1 + 0.0775/2)^(2*10) = 1.954083502
Therefore, the PA factor values for an interest rate of 7.75% and a number of periods of 10 years using the three methods are as follows:
1. Discrete Compounding (Annual): PA = 1.935047075
2. Continuous Compounding: PA = 2.399857382
3. Discrete Compounding (Semi-Annual): PA = 1.954083502
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5. The width of a casing for a door is normally distributed with a mean of 24 inches and a standard deviation of 0.125 inches. The width of a door is normally distributed with a mean of 23.875 inches and a standard deviation of 0.0625 inches. Assume independence. (10) (a) Determine the mean and standard deviation of the difference between the width of the casing and the width of the door? (10) (b) What is the probability that the width of the casing minus the width of the door exceeds 0.25 inches?
(a) The mean of the difference between the width of the casing and the width of the door is 0.125 inches, and the standard deviation is 0.1397 inches.
(b) The probability that the width of the casing minus the width of the door exceeds 0.25 inches is 0.1841 or 18.41%.
(a) Given the mean of casing width (X₁) = 24 inches
Standard deviation of casing width (σ₁) = 0.125 inches
Mean of door width (X₂) = 23.875 inches
Standard deviation of door width (σ₂) = 0.0625 inches
The difference between the width of the casing and the width of the door can be represented as:
Difference (X₁- X₂) = X₁- X₂
The mean of the difference is equal to the difference in means:
Mean of difference = Mean(X₁- X₂)
= Mean(X₁) - Mean(X₂) = 24 - 23.875
= 0.125 inches.
The variance of the difference is the sum of the variances:
Variance of difference = Variance(X₁) + Variance(X₂)
= (σ₁²) + (σ₂²) = (0.125²) + (0.0625²)
= 0.015625 + 0.00390625
= 0.01953125
The standard deviation of the difference is the square root of the variance:
Standard deviation of difference = √(Variance of difference) = √(0.01953125)
= 0.1397 inches.
(b) To find the probability that the width of the casing minus the width of the door exceeds 0.25 inches.
we need to calculate the z-score and then find the corresponding probability from the standard normal distribution.
Let us find the z-score:
z = (x - μ) / σ
x = 0.25 inches, μ = 0.125 inches, and σ = 0.1397 inches.
z = (0.25 - 0.125) / 0.1397
= 0.895
Now, we need to find the probability corresponding to a z-score of 0.895.
Using a standard normal distribution table , we can find this probability. Let's assume it is denoted by P(Z > 0.895).
P(Z > 0.895) = 1 - P(Z < 0.895)
Using the standard normal distribution table , we find that P(Z < 0.895) = 0.8159.
Therefore, P(Z > 0.895) = 1 - 0.8159
= 0.1841.
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In a shop near a school, pencils and erasers are sold. Pens are sold in packs of 10 and erasers in packs of 12. A student decides to buy the minimum number of packages of each variety that results in as many pens as erasers. How many packages should the student buy each? Use correct mathematical language.
The student should buy 6 packages of pens and 5 packages of erasers to get equal numbers of pens and erasers.
A student decides to buy the minimum number of packages of each variety, which results in as many pens as erasers. Pens are sold in packs of 10, and erasers in packs of 12. To determine the minimum number of packages of each type that will result in equal numbers of pens and erasers, the smallest common multiple of 10 and 12 must be calculated.
We can begin the process of finding the smallest common multiple of 10 and 12 by writing down their multiples:
Multiples of 10:
10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120 ...
Multiples of 12:
12, 24, 36, 48, 60, 72, 84, 96, 108, 120 ...
The smallest number that appears in both lists is 60. Therefore, 60 is the smallest common multiple of 10 and 12.
Since pens come in packages of 10 and erasers come in packages of 12, we need to find how many packages are required to obtain 60 of each. If we divide 60 by 10, we get 6.
This means we need to buy 6 packages of pens to get 60. If we divide 60 by 12, we get 5. This means we need to buy 5 packages of erasers to get 60. Hence the student should buy 6 packages of pens and 5 packages of erasers.
Therefore, the student should buy 6 packages of pens and 5 packages of erasers to get equal numbers of pens and erasers.
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