Determine the mean and variance of the random variable with the following probability mass function. f(x)=(216/43)(1/6)x, x=1,2,3 Round your answers to three decimal places (e.g. 98.765).

Answers

Answer 1

Mean:

E[X] = ∑ x f(x) = 1 × f (1) + 2 × f (2) + 3 × f (3) = 51/43 ≈ 1.186

Variance:

Recall that for a random variable X, its variance is defined as

Var[X] = E[(X - E[X])²] = E[X ²] - E[X

Now,

E[X ²] = ∑ x ² f(x) = 1² × f (1) + 2² × f (2) + 3² × f (3) = 69/43

Then

Var[X] = 69/43 - (51/43)² = 366/1849 ≈ 0.198

(each sum is taken over x in the set {1, 2, 3})


Related Questions

Solve for X.
-6x + 14 < -28
AND 3x + 28 < 25

Answers

Answer:

1. -6x + 14 < -28

6x<42

x<7

2.  3x + 28 < 25

3x < -3

x<-1

Hope This Helps!!!

The function f(x)=0.21x + 13.8 can be used to predict diamond production. For this function, x is the number of years after 2000, and f(x) is the value in billions of dollars) of the year's diamond production. Use this function to predict diamond production in 2006. The diamond production in 2006 is predicted to be $billion. (Type an integer or a decimal.) Enter your answer in the answer box ?​

Answers

Answer:

[tex]\boxed {\boxed {\sf \$15.06 \ billion }}[/tex]

Step-by-step explanation:

We are given the function f(x). This is the value of diamond production for the year in billions.

[tex]f(x)= 0.21x+13.8[/tex]

We want to find the value of the diamond production in 2006.

We know that x is the number of years after 2000. The year 2006 was 6 years after 2000 because 2006 - 2000 = 6. Therefore, x (years after 2000) is equal to 6. We can substitute 6 in for x.

[tex]f(6)= 0.21(6)+ 13.8[/tex]

Solve according to PEMDAS (Parentheses, Exponents, Multiplication, Division, Addition, Subtraction).

Multiply 0.21 and 6.

[tex]f(6)= 1.26+13.8[/tex]

Add 1.26 and 13.8

[tex]f(6)=15.06[/tex]

Remember the answer is in billions of dollars.

[tex]f(6)= \$ 15.06 \ billion[/tex]

Diamond production in 2006 is expected to be worth 15.06 billion dollars.

Which graph shows the solution to the system of linear inequalities?
y>2/3x+3
y ≤ -1/3x+2

Answers

Answer:

Graph 2 which has both solid and dashed line

Step-by-step explanation:

Given the linear inequalities :

y>2/3x+3 - - - (1)

y ≤ -1/3x+2 - - - (2)

One quick observation that can be made from the two graphs is the type of line used to plot the two linear inequalities;

Inequalities that uses either the < or > sign are plotted using a dashed line while inequalities with makes use of ≤ or ≥ are plotted using the solid line. Therefore we can conclude that the graph which uses both the solid line and the dashed line to represent the linear inequality conditions is the correct choice.

What is the factored form of 125a^6-64?

Answers

Answer:

(5 a^2 - 4) (25 a^4 + 20 a^2 + 16)

Step-by-step explanation:

Since both terms are perfect cubes, factor using the difference of cubes formula,  

a^3  −  b^ 3 = (a − b) (a^2 + a b + b^2) where a = 5a^2   and  b = 4 .

Divide 30 in the ratio 1 : 4

Answers

Answer:

6 : 24

Step-by-step explanation:

If we are in the ratio of 1 to 4, the total is 1+4 = 5

Divide 30 by 5

30/5 = 6

Multiply each term in the ratio by 6

1  :4

1*6 : 4*6

6 : 24

Answer:

total ratio:

[tex] = 1 + 4 \\ = 5[/tex]

For the portion of 1:

[tex] = 30 \div \frac{1}{5} \\ = 30 \times 5 \\ = 150[/tex]

For the portion of 4:

[tex] = 30 \div \frac{4}{5} \\ = 30 \times \frac{5}{4} \\ = 37.5[/tex]

= 30 : 7.5

what is 2x + 4 = x + 40

Answers

[tex]{\boxed{\boxed { ⎆ Answer :- }}} \ [/tex]

[tex]2x + 4 = x + 40 \\ 2x - x = 40 - 4 \\ x = 36[/tex]

ʰᵒᵖᵉ ⁱᵗ ʰᵉˡᵖˢ ツ

꧁❣ ʀᴀɪɴʙᴏᴡˢᵃˡᵗ2²2² ࿐

X=36

Explanation: cause I said what I said

I need help, and I can’t figure it out

Answers

Step-by-step explanation:

put the value of f(x)

I think that you know

hope it is helpful for you

Answer:

4x + 2h - 1

Step-by-step explanation:

[tex]\frac{f(x+h) - f(x)}{h}[/tex]

[tex]\frac{(2(x+h)^2 - (x + h) + 5) - (2x^2 - x + 5)}{h}[/tex]

[tex]\frac{2x^2 + 4xh + 2h^2 - x - h + 5 - 2x^2 + x - 5}{h}[/tex]

[tex]\frac{4xh + 2h^2 - h}{h}[/tex]

4x + 2h - 1

Please answer!<333 xx

Answers

12. X= 6

14. B= -11

16. N= 15

Answer:

q12. [tex]x=6[/tex]

q14. [tex]b=-11[/tex]

q16. [tex]n=15[/tex]

Step-by-step explanation:

Q12.

[tex]-1=\frac{x}{-6}[/tex]

Flip the equation:

[tex]\frac{x}{-6} =-1[/tex]

Multiply both sides by 6/(-1)

[tex](\frac{6}{-1} )[/tex] × [tex](\frac{-1}{6}x )[/tex] = [tex](\frac{6}{-1} )[/tex] × [tex](-1)[/tex]

[tex]x=6[/tex]

Q14.

[tex]5b=-55[/tex]

[tex]b=\frac{-55}{5}[/tex]

[tex]b=-11[/tex]

Q16.

[tex]-3n=-45[/tex]

[tex]n=\frac{-45}{-3}[/tex]

[tex]n=15[/tex]

hope this helps.....

Name the following polynomial based on its degree and number of terms x to the power of 2 plus 6x - 4

Answers

Answer:

x²+6x-4 is answer maybe

what term can you add to
[tex] \frac{5}{6} x - 4[/tex]
to make it equivalent to
[tex] \frac{1}{2} x - 4[/tex]

Answers

9514 1404 393

Answer:

  -1/3x

Step-by-step explanation:

We want to find the term 'a' such that ...

  (5/6x -4) + a = (1/2x -4)

Add 4-1/2x to both sides.

  (5/6 -1/2)x -4 +4 +a = 0

  (5/6 -3/6)x + a = 0 . . . . . . express the fractions using a common denominator

  1/3x + a = 0 . . . . . . . . . . simplify the difference

  a = -1/3x . . . . . . . . . . .subtract 1/3x

The term you can add to make the desired equivalent is -1/3x.

A business woman wants to open a coffee stand across the street from a competing coffee company. She notices that the competing company has an average of 170 customers each day, with a standard deviation of 45 customers. Suppose she takes a random sample of 31 days. Identify the following to help her decide whether to open her coffee stand, rounding to the nearest whole number when necessary:
μ =_____customers per day
σ =_____customers per day
n =____
μ-x =____
σ-x =_____customers per day

Answers

Answer:

μ = 170 customers per day

σ = 45 customers per day

n = 31

[tex]\mu_x = 170[/tex]

[tex]\sigma_x = 8[/tex]

Step-by-step explanation:

Central Limit Theorem

The Central Limit Theorem establishes that, for a normally distributed random variable X, with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean [tex]\mu[/tex] and standard deviation [tex]s = \frac{\sigma}{\sqrt{n}}[/tex].

For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.

She notices that the competing company has an average of 170 customers each day, with a standard deviation of 45 customers.

This means that [tex]\mu = 170, \sigma = 45[/tex]

Suppose she takes a random sample of 31 days.

This means that [tex]n = 31[/tex]

For the sample:

By the Central Limit Theorem, the mean is [tex]\mu_x = 170[/tex] and the standard deviation is [tex]\sigma_x = \frac{45}{\sqrt{31}} = 8[/tex]

Two different formulas of an oxygenated motor fuel are being tested to study their road octane numbers. The variance of road octane number for formula 1 is σ12=1.5, and for formula 2 it is σ22=1.2. Two random samples of size n1=15 and n2=20 are tested, and the mean octane numbers observed are x¯1=89.0 fluid ounces and x¯2=92.2 fluid ounces. Assume normality.

a. Test the hypothesis that the formulations are equal versus the hypothesis that formulation 2 produces a higher mean road octane number than formulation 1. Calculate z0=
b. Calculate a 95% two-sided confidence interval on the mean difference road octane number.

Answers

Answer:

Step-by-step explanation:

a)

zo=(89.0-92.2)/sqrt((1.5/15)+(1.2/20))

zo=-8.00

p-value=0.0000

Reject the null hypothesis.

b)

95% confidence interval for difference

=(89-92.2)+/-1.96*sqrt((1.5/15)+(1.2/20))

=-3.2+/-0.78

=(-3.98, -2.42)

add 10ft 3in + 3ft 9in + 8ft 10in​

Answers

22 feet 10 inches I hope I am right

???????????????????????????

Answers

Answer:

y-(-20)=1(x-(-10))

Step-by-step explanation:

If you're really in college you should know this, but here's the explanation:

m= -9-(-20)

      1-(-10)

  = 11

     11

m = 1

The equation is y-y^1=m(x-x^1)

Replace the y^1, m, and x^1 from the first point

You get y-(-20)=1(x-(-10))

Or simplify that into y+20=x+10

You can also simplify it more but I don't think you need that for that question

The following data were obtained from 4 people Pre-Test Value Post-test Value 43 42 28 29 31 30 28 25 You may also assume that the sample standard deviation for the four differences is 1.6. What is the correct t-statistic and the degrees of freedom for these data

Answers

Answer:

Test statistic = 1.25

Degree of freedom = 3

Step-by-step explanation:

The following data were obtained from 4 people

Pre-Test Value Post-test Value __ d

43 ________42 _________ 1

28_______ 29 ________ - 1

31 ________30 _________ 1

28 ________ 25 _________ 3

μd = (1 + - 1 + 1 + 3) / 4 = 4 /4 = 1

The mean difference, μd = 1

The standard deviation of difference, Sd = 1.6

The test statistic = μd / (Sd / √n)

Test statistic = 1 / (1.6/2) = 1 / 0.8

Test statistic = 1.25

Degree of freedom, = n - 1 = 4 - 1 = 3

The number of runners in the London Marathon on 25th April, 2010 was 37 527.

Work out an estimate for the number of these runners whose birthday was on that day.

Answers

Answer:

Hi 34

Step-by-step explanation:

Hi

Which one of the following is a better buy: a large pizza with a 14-inch diameter for $13.00 or a medium pizza with a 7-inch diameter for $4.00?
O Large Pizza
Medium Dizz

Please help :)

Answers

Answer:

Large pizza is the answer

The 100th term of 8, 8^4, 8^7, 8^10, …

Answers

Answer:

[tex]8^{298} \\8^{3(n-1)+1}[/tex]

Step-by-step explanation:

Answer:

8^298

Step-by-step explanation:

n = 1, 8^(1 + 0 * 3)

n = 2, 8^(1 + 1 * 3)

n = 3, 8^(1 + 2 * 3)

n = 4, 8^(1 + 3 * 3)

The exponent of 8 is 1 added to product of 1 less than the term number multiplied by 3.

n = n, 8^(1 + [n - 1] * 3) = 8^(1 + 3n - 3) = 8^(3n - 2)

For n = 100, the exponent is

3n - 2 = 3(100) - 2 = 300 - 2 = 298

Answer: 8^298

A line contains the points (3,1) and (-6,4) what is the equation for this line in slope intercept form

Answers

Answer:

y = (-1/3)x + 2

Step-by-step explanation:

Since points (3,1) and (-6,4) lie on y = (-1/3)x + c , it should satisfy the this equation. Thus, intercept is 2.

Answer:

m = -⅓

Step-by-step explanation:

m = (y2- y1)/(x2 - x1)

m = (4 -1)/(-6-3)

m = -⅓

Which of the following is an even function?
g(x) = (x – 1)2 + 1
g(x) = 2x2 + 1
g(x) = 4x + 2
g(x) = 2x

Answers

Answer:

B. g(x) = 2x² + 1

Step-by-step explanation:

Even function has following property:

g(x) = g(-x)

It is easy to show this works with the second choice only. All the others don't work:

g(x) = (x - 1)² + 1g(-x) = (-x - 1)² + 1

This is not correct as x - 1 ≠ -x - 1 so as their squares, so g(x) ≠ g(-x)

The last two choices are not even similarly.

Answer:

B. g(x) = 2x2 + 1

Correct on edge

If it takes Ohenhen 10km to pass to Emma and it takes Emma 8km to pass to Omusi and considering Ohenhen & Omusi are at perpendicular ends from Emma. What's the distance between Ohenhen and Omusi?​

Answers

Answer:

12.81 km

Step-by-step explanation:

Pythagoras formula for right-angled triangles.

this scenario just says that Emma is the corner point of that triangle with an angle of 90 degrees.

the distance between Ohenhen and Omusi is the baseline (Hypotenuse c) of that triangle. and the distances to Emma are the sides a and b.

so the formula is

c² = a² + b² = 10² + 8² = 100 + 64 = 164

[tex]c = \sqrt{164} [/tex]

c ≈ 12.81 km (rounded to the nearest hundredth).

What is 35 degrees Celsius in Fahrenheit equal

Answers

Answer:

95°Fahrenheit

hipe this helps you

48. What is the volume of the cuboid below? 3cm 2cm 2cm

Answers

Answer:

Cuboid = width*height*length

Cuboid = 24 cm^2

f it take 20 minutes to boil 6 crates of eggs, how much time will it take to boil 18 crates of eggs​

Answers

a hour,.....................

I need at least two more sentences in regards with this assignment. Note the included photo. Please come up with two proper sentences following the assignments instructions. Ps. Don’t try to steal points from this or you will be reported

Answers

Answer:

A={x: x is a cat}

B={x: x likes climbing on trees}

My little cat Louis likes climbing on trees (Louis is in the intersection of the two sets)

A={x: x is a town in the USA}

B={x: x is a town in the UK}

To improve my English I'd like to go on holiday to a town in the USA, but a town in the UK would work too (the town shall be in the union of the two sets)


Now actually compute 2 - 8

Answers

Answer:

the answer is -6. you just subtract 2 with 8

what was the original price of the car? MUST SHOW ALL STEPS OF THE PROCESS.

Answers

Answer:

19219.48

Step-by-step explanation:

16540x0.162+16540

The original price would be 100%

It was marked down 16.2%

100 % - 16.2% = 83.8%

The price you paid was 83.8% of the original price.

To find the original price divide the amount you paid by the percentage of the original price:

16,540 / 0.838 = 19.737.47

Original price: $19,737.47

what is nine and three hundred twenty-one thousandths in decimal notation?

Answers

Answer:

Step-by-step explanation:

9.0321 ? Im not sure but i tried

a. The first five terms of n^2 + 5 are


Answers

Given:

The nth term of a sequence is:

[tex]n^2+5[/tex]

To find:

The first five terms of the given sequence.

Solution:

The given sequence is:

[tex]a_n=n^2+5[/tex]

For n=1,

[tex]a_1=1^2+5[/tex]

[tex]a_1=1+5[/tex]

[tex]a_1=6[/tex]

For n=2,

[tex]a_2=2^2+5[/tex]

[tex]a_2=4+5[/tex]

[tex]a_2=9[/tex]

For n=3,

[tex]a_3=3^2+5[/tex]

[tex]a_3=9+5[/tex]

[tex]a_3=14[/tex]

For n=4,

[tex]a_4=4^2+5[/tex]

[tex]a_4=16+5[/tex]

[tex]a_4=21[/tex]

For n=5,

[tex]a_5=5^2+5[/tex]

[tex]a_5=25+5[/tex]

[tex]a_5=30[/tex]

Therefore, the first five terms of the given sequence are 6, 9, 14, 21, 30.

nit 4 Topic 3 HW Sets Applications e Sunday by 11:59pm Points 100 Submitting an external tool Question How many subsets and proper subsets does the set M = {1,2,3} have? Select the correct answer below:​

Answers

Answer:

ghthtf

Step-by-step explanation:

tygtgg

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