A help desk has two employees with one working during the day and one working at night. The number of hours the first employee works (X1) is normally distributed with mean 8.6 and standard deviation 0.1 and the number of hours the second employee works (X2) is normally distributed with mean 8.4 and standard deviation 0.9. Suppose that the amount of time that the employees overlap (X3) is normally distributed with mean 0.2 and standard deviation 0.2. Finally, assume that X1, X2, and X3 are independent. We are interested in the total time that the help desk has an employee present, i.e., Z = X1 + X2 - X3. A) What is the expected value of Z, the total time that the help desk has an employee present? B) What is the variance of Z? C) What is the probability that Z is between 15.9 and 16.1? D) What is the probability that Z is greater than 16?

Answers

Answer 1

Answer:

a) 16.8 hours.

b) 0.86 hours squared.

c) 0.0606 = 6.06% probability that Z is between 15.9 and 16.1.

d) 0.8051 = 80.51% probability that Z is greater than 16

Step-by-step explanation:

Normal Probability Distribution:

Problems of normal distributions can be solved using the z-score formula.

In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the z-score of a measure X is given by:

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.

Sum of normal variables:

When we add normal variables, the mean is the sum of each mean, while the variance is the sum of each variance. The standard deviation is the squared root of the variance.

In this question:

X1: Mean 8.6, standard deviation 0.1

X2: Mean 8.4, standard deviation 0.9

X3: Mean 0.2, standard deviation 0.2

Z = X1 + X2 - X3.

Mean:

[tex]\mu = 8.6 + 8.4 - 0.2 = 16.8[/tex]

Variance:

[tex]\sigma^{2} = 0.1^2 + 0.9^2 + 0.2^2 = 0.86[/tex]

Standard deviation:

[tex]\sigma = \sqrt{\sigma^{2}} = \sqrt{0.86} = 0.9274[/tex]

A) What is the expected value of Z, the total time that the help desk has an employee present?

[tex]\mu = 16.8[/tex]

So 16.8 hours.

B) What is the variance of Z?

[tex]\sigma = 0.86[/tex]

So 0.86 hours squared.

C) What is the probability that Z is between 15.9 and 16.1?

This is the pvalue of Z when X = 16.1 subtracted by the pvalue of Z when X = 15.9. So

X = 16.1

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

[tex]Z = \frac{16.1 - 16.8}{0.9274}[/tex]

[tex]Z = -0.75[/tex]

[tex]Z = -0.75[/tex] has a pvalue of 0.2266

X = 15.9

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

[tex]Z = \frac{15.9 - 16.8}{0.9274}[/tex]

[tex]Z = -0.97[/tex]

[tex]Z = -0.97[/tex] has a pvalue of 0.1660

0.2266 - 0.1660 = 0.0606

0.0606 = 6.06% probability that Z is between 15.9 and 16.1.

D) What is the probability that Z is greater than 16?

This is 1 subtracted by the pvalue of Z when X = 16. So

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

[tex]Z = \frac{16 - 16.8}{0.9274}[/tex]

[tex]Z = -0.86[/tex]

[tex]Z = -0.86[/tex] has a pvalue of 0.1949

1 - 0.1949 = 0.8051

0.8051 = 80.51% probability that Z is greater than 16


Related Questions

A sample with a mean of M = 8 has EX = 56. How many scores are in the sample?
The number of scores is n =

Answers

Answer:

[tex]n = 7[/tex]

Step-by-step explanation:

Given

[tex]\bar x = 8[/tex] --- the mean

[tex]\sum x = 56[/tex] --- sum of scores

Required

The number of scores (n)

This is calculated as:

[tex]\bar x = \frac{\sum x}{n}[/tex]

Make n the subject

[tex]n = \frac{\sum x}{\bar x}[/tex]

[tex]n = \frac{56}{8}[/tex]

[tex]n = 7[/tex]

2 trifles cost 9 pound
How much will 6 trifles cost?

Answers

2 = 9

9 ÷ 2 = 4.5

4.5 x 6 = 27

It will cost 27 pounds.

Hope this helps; have a great day!

For the following right triangle, find the side length x.

Answers

Answer:

17

Step-by-step explanation:

We can use the pythogorean theorem which is,

[tex] {a}^{2} + {b}^{2} = {c}^{2} [/tex]

Where c = Hypotenuse

b and a = Legs of the triangle

We have to find the hypotenuse. So let's keep the value of it as x.

we can form an algebraic equation to solve for x

[tex] {15}^{2} + {8}^{2} = {x}^{2} \\ 225 + 64 = {x}^{2} \\ 289 = {x}^{2} \\ x = \sqrt{289} \\ x = 17[/tex]

Holli’s cheerleading uniform cost $92.58. There are 13 cheerleaders on the squad. How much will it cost for all of the uniforms?

ASAP!

Answers

Answer:105.8

Step-by-step explanation: you dived

Use any strategy to solve 3,600 divided by 9. Upload your work.

Answers

Answer:

400

Step-by-step explanation:

3600/9=400

36/9=4

add the zeros back in after

Answer:

400

Step-by-step explanation:

I hope this helps you

. Mr. View is 8 years older than Ms. Sun. In 7 years, the sum of their ages will be 110. How old are they now?​

Answers

Mr. View is now 63, while Ms. Sun is now 47. You’d have to divide 110 in half, this would give you 55. Then subtract 8 from 55, to give you Ms. Suns’ age. To find out Mr. Views age, you then subtract 47 from 110, and you’d then get 63.

What is the value of g(-4)
I <-4
gir) =
+32 + 11, 1 > -4
A.
..1
OB
15
OCH 27
OD.

Answers

Answer:

e a d

Step-by-step explanation:

This is number three Nd I neeed help with this I can help you with anything

Answers

Answer:

a. False

b. False

c. True

d. True

e. True

1. The circumference of a circle is 16p centimeters.
(a) Find the diameter of the circle.
(b) Find the area of the circle.

Answers

Answer: Diameter: 8

              Area:  201.1

             

Step-by-step explanation:

Diameter: Use the formula for the area of a circle:

Use the formula for the area of a circle:

A=πr2

Here, the area is 16π:

16π=πr^2

Divide both sides by  π:

16=r^2

Take the square root of both sides:  √16=√r^2

4=r

Since the radius of the circle is 4, the diameter is twice that:

d=4×2=8

Area:

Formula:

A = π r^2

A= Area R= Radius

Add Radius

A= π 8^2

Solve:

Simplify  π⋅8^2

Exact Form:

A=64π

Decimal Form:

A=201.06192982

use the graph below to write the equation of the function

Answers

Answer:

c

Step-by-step explanation:

gefhhfeyjhtwgi15287

Please help grades close today

Answers

Answer:

Step-by-step explanation:

17. 1 foot=12 inches

So subtract 12 from 28

28-12

=16

Lena's puppy will grow 16 inches more.

18. The kittens can be

3.4, 3.3, 3.2, 3.1, 3, etc. ( units in ounces)

There are a lot of combinations so you have to find out ALL the possible combined values. ( I don't think I can fit all of them on here you will probaly have to do some work for it)

Hopefully this helps!!!

☁️ Answer ☁️

17. The puppy will grow 16 inches

One foot equals 12 inches. Lena's puppy will grow to be at most 28 inches. 28-12=16 inches.

18. 24.5

the possible values of the combined weights of the kittens is not more than 24.5 ounces. Since there are 7 kittens, the combined weight of the kittens is 7w, therefore the above expression could be read as "The combined weight of the kittens is less than 24.5 ounces

Which of the following is not true about the boundary line in the graph of a linear inequality in two​ variables?

Answers

Answer:

The correct answer is D

Step-by-step explanation:

Boundary points are NOT always solutions

The statement  not true about the boundary line in the graph of a linear inequality in two​ variables is he point on boundary line are always solutions to the linear inequality

What does boundary line in graph of a linear inequality in two variable represent ?

The graph of an inequality in two variables is the set of points that represents all solutions to the inequality. A linear inequality divides the coordinate plane into two halves by a boundary line where one half represents the solutions of the inequality. The boundary line is dashed for > and < and solid for ≤ and ≥.

According to the question

Boundary line in graph of a linear inequality in two variable represents :The boundary line is dashed or strict for > and < The boundary line is solid or non strict  for ≤ and ≥. boundary line divides the coordinate plane into two halves boundary line where one half represents the solutions of the inequality

Hence, The statement  not true about the boundary line in the graph of a linear inequality in two​ variables is he point on boundary line are always solutions to the linear inequality.

To know more about boundary line in graph of a linear inequality in two variable represent here:

https://brainly.com/question/21397250

#SPJ3

Point P on a coordinate plane, located 3 units to the left of the vertical axis and 2 units below the horizontal axis.
A. (–3, –2)
B. (–3, 2)
C. (–2, –3)
D. (–3, –3)

Answers

Answer:

A. (-3,-2)

follow me please
Answer : A. (-3,-2)
This is the correct answer

Yana needs at least $31.50 for art supplies. He earns $3.50 per day as a dog walker. Which graph represents the number of days Yana must work to earn enough money to buy the art supplies? A. 84456 B. 84455 C. 84454 D. 84453

Answers

Answer:

9 days

Step-by-step explanation:

31.50÷3.50 is 9 and 9×3.50 is 31.50

pls help i have 5 minutes til it’s due

Answers

Answer:

x=115

Step-by-step explanation:

Straight angle = 180 degrees...

65 is accounted for so...

180-65=115

115 degrees is your final answer :)

Answer:

115

Step-by-step explanation:

x° = 180° - 65°

(Linear pair angles)

x° = 115°

x = 115

18)
Find the area of a regular pentagon with an apothem of 2.75 cm and a side length of 4 cm, (round to the nearest whole number)
A)
14 cm
B)
28 cm
C)
56 cm
D)
112 cm?

Answers

Answer:

B) 28 cm^2

Step-by-step explanation:

First, find the perimeter 5*4=20

A= ½ 2.75(20) = 27.5

(round to the nearest whole number)

Got it right on the test

If LW = 5x + 2 and LJ = 11x + 2 in the parallelogram below. Find LW.

Answers

Answer:

A. 12

Step-by-step explanation:

Recall: one of the properties of a parallelogram is that the diagonals bisect each other. This means that:

LJ = 2(LW)

11x + 2 = 2(5x + 2)

11x + 2 = 10x + 4

11x + 2 - 2 = 10x + 4 - 2

11x = 10x + 2

11x - 10x = 10x + 2 - 10x

x = 2

✅LW = 5x + 2

Plug in the value of x

LW = 5(2) + 2

LW = 10 + 2 = 12

When the sum of a number and 14 is
divided by 3, the result is 4.

Answers

Answer:

it is 4.6 sorry girl

Step-by-step explanation:

Answer:

Step-by-step explanation:

4.6=4 3/5=23/5

Find the area of the shape shown below.

Answers

Answer: 4, 800

Step-by-step explanation:

Which shoe size is the mode?

Answers

Answer:

6

Step-by-step explanation:

PLEASE HELP!!!

I’ve been working on this equation for 2 days now and can’t get the right answer I think this is the right way to do it but I’m not sure

Solve for Y in the equation (5y-29) + (3y+19) = 180

Answers

Answer:

A - they are vertical angles so they are equal to each other

b - dont really know this one

c - y=24 and 7 and 8 = 89

Step-by-step explanation:

You messed up because the angles given are not supplementary the angles given that are next to 7 and 8 are vertical then we can setup an equation which would be 5y-29=3y+19 and solve for y

step 1 add 29 to each side

5y=3y+48

step 2 subtract each side by 3y

2y=48

step 3 divide each side by 2

y=24

then we plug in 24 to one of the expressions

5(24)=120

120-19=101

but we are not done yet because it is asking for the value of angle 7 and 8

because angle 7 is supplementary to both all we have to do is subtract 101 from 180

180-101=89 so 7 and 8 =89

hope this helps :D

Combine the two terms: 3x + 8 + -5x + 2​

Answers

Answer:

10 - 2x

Step-by-step explanation:

3x + 8 + - 5x + 2​

- 2x + 8 + 2

10 - 2x

Answer:

-2x+10

Step-by-step explanation:

Combine the variables

-5x+3x= -2x

Combine the other numbers

 8+2= 10

-2x+10

7. In the figure, AABC-AXYZ. What is the perimeter of AABC? Show your work.

Answers

The answer would be 36

giving brainliest!!!

Answers

Answer:

133 square centimeters

Step-by-step explanation:

Answer:

Surface A≈146.25 square centimeters

Step-by-step explanation:

Is sin( - 7) positive or negative? (Why?)

Answers

-.66 this is because when you put it into a scientific calculator sin then -7 and round up you get -.66

Nora is going to earn $300 from her summer job. Combined with her savings, Nora will then have $1,500 toward her music school. How much money does Nora have in her savings?

Answers

Answer:

1200

Step-by-step explanation:

1,500-300=1200

PLEASE HELP AND I KNOW A MANAGER THAT CAN GET YOUR WHOLE EMAIL BANNED SO DON'T TRY ANYTHING AND I KNOW IF YOU'RE GUESSING OR NOT

Answers

Answer:

B. 20

Step-by-step explanation:

We need to find a common denominator for 1/5, 1/3, and 3/10, which would be 30. 1/5 = 6/30, 1/3 = 10/30, and 3/10 = 9/30. If we add these together we get 25/30. This leaves 5/30 covered in sprinkles.

Now we need to find what 5/30 of 120 is. We can simplify 5/30 to 1/6. 120 divided by 6 is 20. So, 20 apples are covered in sprinkles.

Answer:

it"s B

Step-by-step explanation:

I just don't have the energy to explain why.  sorry pls dont get me banned

pleaseeee help I will mark you brainiest!!!!!!

Answers

Answer:

I think it is -2,a+c, than b

PLS HELP!!! :((

Find the volume....

Answers

Answer:try this if u can 1330

Step-by-step explanation:

Triangular prisms

Remember the formula for calculating volume is: Volume = Area by height. V = A X h.

For a triangle the area is calculated using the formula: Area = half of base by altitude. A = 0.5 X b X a.

So to calculate the volume of a triangular prism, the formula is: V = 0.5 X b X a X h

Answer:

760in^3

Step-by-step explanation:

You multiple length x width x height

which is 19x10x14

2660 in^3

7) In Emily's bead collection, 1/2 of her beads are red and 1/4 of her beads
are green. What fraction of her beads are NOT red?

Answers

1/2 of her beads
hope this helps!!
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