Installation of certain hardware takes a random amount of time. The installation times form a normally distributed distribution with a standard deviation 5 minutes and a mean of 45 minutes. A computer technician installs the hardware on 31 different computers. You are interested to find the probability that the mean installation time for the 31 computers is less than 43 minutes. What is the probability that the mean installation time for 31 computers is less than 43 minutes.

Answers

Answer 1

To solve this question, the normal distribution and the central limit theorem are used.

Doing this, there is an 0.0129 = 1.29% probability that the mean installation time for 31 computers is less than 43 minutes.

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First, these concepts are presented, then we identify mean, standard deviation and sample size, and then, we find the desired probability.

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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.

------------------------------------

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

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

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Mean of 45, standard deviation of 5:

This means that [tex]\mu = 45, \sigma = 5[/tex]

Sample size of 31:

This means that [tex]n = 31, s = \frac{5}{\sqrt{31}}[/tex]

------------------------------------

Probability the sample mean is less than 43:

This is the p-value of Z when X = 43, so:

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

By the Central Limit Theorem

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

[tex]Z = \frac{43 - 45}{\frac{5}{\sqrt{31}}}[/tex]

[tex]Z = -2.23[/tex]

[tex]Z = -2.23[/tex] has a p-value of 0.0129.

Thus, 0.0129 = 1.29% probability that the mean installation time for 31 computers is less than 43 minutes.

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Related Questions

An investment pays 21% interest compounded weekly what percent as a decimal is the effective annual yield? Enter your answer as a decimal rounded to four decimal places.

Answers

9514 1404 393

Answer:

  0.2332

Step-by-step explanation:

The relationship between the effective annual yield (e) and the nominal annual interest rate (r) compounded n times per year is ...

  e = (1 +r/n)^n -1

For weekly compounding, we have n=52, so ...

  e = (1 +0.21/52)^52 -1 = 0.2332 . . . . . . . about 23.32%

Consider the given statement. Determine whether its is equivalent to the given statement, a negation, or neither. Attached is the photo reference.

Answers

Answer:

1. Negation

2. Equivalent

3. Neither

4. Neither

Step-by-step explanation:

p ^ ~q

~q → p~

~q ∨ p

~p ∨q

Use the distributive property to remove the parentheses.
I’m so bad at math so I need help :/

Answers

Answer:

27x^5 + 30x^4

Step-by-step explanation:

Multiply 3x^3 out of (9x^2 + 10x)

Step 1. Multiply 3x^3 x 9x^2

Answer: 27x^5

Step 2. Multiply 3x^3 x 10x

Answer: 30x^4

“Add these two products together”

27x^5 + 30x^4

Hope this helps!

Love you.

- doomdabomb

please help
Question: 6b = 18
Answer: ?

Answers

Answer:

6b=18

b=18/6

b=3

.

.

.

.

.

.

Answer:

6b=18

b=18/6

b=3

.

Step-by-step explanation:

Find the probability
A bag contains 6 red marbles, 8 blue marbles, and 9 green marbles. What is the probability of choosing a blue marble?

Answers

Answer is in a box.

The bag contains 6 red marbles, 8 blue marbles and 9 green marbles, that is 23 marbles.

The probability that one of the 23 marbles will be picked is 1 or 100%, we are picking a marble for sure.

So what is the probability you will pick for example one of the 6 red marbles? It is 6 out of 23 but since we need percentages multiply by 100,

[tex]\frac{6}{23}\cdot100\approx26.09\%[/tex]

The probability to pick a blue marble is,

[tex]\boxed{\frac{8}{23}}\cdot100\approx34.78\%[/tex]

And the probability to pick a green marble is,

[tex]\frac{9}{23}\cdot100\approx39.13\%[/tex]

To check that everything is right you can sum all the probabilities; the probability that it will be either red, blue or green is 100% so the individual probabilities must sum to 100%, and they do,

[tex]26.09\%+34.78\%+39.13\%=100\%[/tex]

Hope this helps :)

Help 50 point question

Answers

Answer:

1/3

Step-by-step explanation:

.444444444(repeating)- .111111111111(repeating)

.44444444......

-.11111111........

--------------------

.33333333........

Let x = .3333333.....

10x = 3.3333333.....

Subtract the first equation from the second

10x = 3.33333.....

-x =     .33333.....

--------------------------

9x = 3

x = 3/9

x = 1/3

---------------------------

Find the x-and y-intercepts of the graph of 4x + y = 28. State your answers as
whole numbers or as improper fractions in simplest form.

Answers

Answer:

at x-intercept, y = 0

4x = 28

x = 7

x intercept = (7,0)

at y-intercept, x = 0

y = 28

y intercept = (0,28)


$88 tickets to the San Francisco 49ers game are offered at a 15%
discount. What is the sale price?

Answers

Answer:

74.80

Step-by-step explanation:

First find the discount

88 * 15%

88*.15

13.2

Subtract the discount from the original price

88-13.2

74.80

find the surface area of the prism

Answers

Answer:

114 cm²

Step-by-step explanation:

Surface area of the rectangular prism,

2×(wl+hl+hw)

=2×(3×8+3×8+3×3)

= 2×(24+24+9)

= 2×(57)

=114 cm²

PLEASE JUST GIVE ME THE EQUATION

Answers

Answer:

y=4/3x-3

Step-by-step explanation:

4 l to 250 miles ratio​

Answers

Answer:

See below.

Step-by-step explanation:

Are you sure it's 4 liters to 250 miles, and not 4 liters to 250 milliliters?

If it is 4 liters to 250 miles, then it equals

0.016 liter : 1 mile

If it is 4 liters to 250 ml, then it is

4 liters : 250 ml

4 liters : 0.25 liter

16 liters : 1 liter

16 : 1

HELP UUUURRRRRRRGGGGGEEEEEENNNNTTTTT PLLLLZZZZZ IM BAD AT MATHHHHHHHH

Answers

Answer:

-1 8/9

Step-by-step explanation:

w + ( - x)

w = -5/9

z = 4/3

Input:

-5/9 + ( -4/3)

-5/9 - 4/3

-4/3 * 3/3 = -12/9

-5/9 - 12/9 = -17/9 = -1 8/9

If my answer is incorrect, pls correct me!

If you like my answer and explanation, mark me as brainliest!

-Chetan K

At what rates did she invest?
$1400 invested at ____%
$900 invested at ____%

Answers

9514 1404 393

Answer:

$1400 at 8%$900 at 10%

Step-by-step explanation:

The 1-year interest is simply the invested amount times the interest rate.

Let r represent the lower interest rate. Then r+0.02 is the higher rate, and the total interest earned is ...

  1400r + 900(r +.02) = 202

  2300r +18 = 202 . . . . . . . . . .simplify

  2300r = 184 . . . . . . . . . .subtract 18

  r = 184/2300 = 0.08 = 8% . . . . . . divide by the coefficient of r

$1400 was invested at 8%.

$900 was invested at 10%.

$400 invested at 8%
$900 invested at 10%

Natalie's team needs to make a decision on how to handle a big product recall. People on the team have a lot of strong opinions. Management wants everyone to come to a consensus and to find a solution that everyone can support. What's the best way to get to a consensus? a) Everyone on the team talks until the entire team agrees on one decision. O b) Everyone on the team discusses options and then votes. O c) The team passes the decision-making responsibility to an outside person. O di The team leader makes a decision without input from the other members.

Answers

B) Everyone on the team discusses options and then and then votes.

complete the equation describing how x and y are related.

Answers

Answer:

y=-2x+1

Step-by-step explanation:

The slope of the line is (y(2)-y(1))/(2-1)=(-3+1)/1=-2. The equation of the line is y=mx+(y intercept), y=-2x+1

The complete equation describes how x and y are related y=-2x+1.

We have given, the equation,

We have to determine the complete equation describing how x and y are related.

What is the formula for the slope?

The slope of the line is(m)=y2-y1/x2-x1

Where m is the slope,

Therefore we get,

(y(2)-y(1))/(2-1)

=(-3+1)/1

=-2.

The equation of the line is y=mx+(y-intercept), y=-2x+1.

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Beth has just received an inheritance of $500,000 and would like to be able to make quarterly withdrawals over the next 20 years. She decides on an annuity that pays 6.4%, compounded quarterly. How much will her quarterly payments be to draw the account down to zero at the end of 20 years? Quarterly Payments =​

Answers

The amount Beth would be able to withdraw quarterly from her inheritance over the next 20 years is Quarterly Payments ≈ $11,124.53

The given parameters in the question;

Present value of inheritance, PV = $500,000

The number of years of withdrawal, n = 20 years

Interest rate, i = 6.4%

The required parameter;

The amount Beth would be able to withdraw quarterly over the next 20 years to draw the account down to zero, given a quarterly interest rate of 6.4%

Method

The required parameter is given by the payment formula

The question is related with annuity given that withdrawals will be made quarterly

The question seeks to find how much she can withdraw so as to exhaust the balance in 20 years

The amount she can withdraw quarterly is given by the payment formula as follows;

[tex]\mathbf{PMT = PV \times \dfrac{i}{1 - \left(1 + i\right)^{-n}}}[/tex]

Where;

PMT = The amount of quarterly payments

PV = The present value of the investment = $500,000

i = The interest rate = 6.4%

n = The number of years = 20 years

Therefore, we get;

[tex]\mathbf{PMT = 500,000 \times \dfrac{\dfrac{0.064}{4} }{1 - \left(1 + \dfrac{0.064}{4} \right)^{-4 \times 20}} \approx 11,124.53}[/tex]

The amount she can withdraw quarterly for the next 20 years ≈ $11,124.53

Quarterly payment, PMT = $11,124.53

Learn more about annuity here;

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Is -1 rational or irrational

and is √3 + -1 Rational or irrational

explain if u can pls​

Answers

Answer:

-1: rational

√3 + -1: irration

Step-by-step explanation:

A rational number is negative, if its numerator and denominator are of the opposite signs.

Hope this helps <3

Geometry please need help I don’t know to do this try to help me please!!!!

Answers

Step-by-step explanation:

Note that since [tex]\triangle ABC \cong \triangle DEF,[/tex] we can see from the figure that [tex]\angle B[/tex] and [tex]\angle E[/tex] have the same measure.

a) To solve for the length of [tex]\overline{AB},[/tex] we write

[tex]3x + 6 = 4x \Rightarrow x = 6[/tex]

b) Since the two triangles are congruent, we can say that [tex]\angle A = \angle D[/tex] so we can write

[tex]6y + 12 = 8y + 2[/tex]

Solving for y, we get

[tex]2y = 10 \:\Rightarrow \:y = 5[/tex]

3 x {(300 - 70 ÷ 5) - [3 x 23 - (8 - 2 x 3)]}

A.657
B.2433
C. -843

Answers

Answer:

657

Step-by-step explanation:

pemdas

The value of the expression 3 x {(300 - 70 ÷ 5) - [3 x 23 - (8 - 2 x 3)]} is 657.

Hence option A is correct.

Given is an expression, 3 x {(300 - 70 ÷ 5) - [3 x 23 - (8 - 2 x 3)]}, we need to simplify it,

Let's break down the expression step by step:

First, let's simplify the expression inside the innermost parentheses:

8 - 2 x 3 = 8 - 6 = 2

Next, let's simplify the expression inside the brackets:

3 x 23 - 2 = 69 - 2 = 67

Now, let's substitute the simplified expression inside the brackets back into the original expression:

(300 - 70 ÷ 5) - 67

Next, let's simplify the expression inside the remaining parentheses:

70 ÷ 5 = 14

Now, let's substitute the simplified expression inside the parentheses back into the expression:

(300 - 14) - 67

Next, let's simplify the expression inside the remaining parentheses:

300 - 14 = 286

Now, let's substitute the simplified expression inside the parentheses back into the expression:

286 - 67

Finally, let's perform the subtraction:

286 - 67 = 219

Now, let's multiply the result by 3:

3 x 219 = 657

Therefore, the value of the expression 3 x {(300 - 70 ÷ 5) - [3 x 23 - (8 - 2 x 3)]} is 657.

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John and mike got paid $40.00 for washing
car. John work one hour, mike worked 1.5 hrs.
How much do they get paid for time worked?

Answers

This question is incomplete , l can’t answer it . You have to say how much minutes or hours they work to get paid $40 ,if you just say that John’s work one hour and Mike work 1.5 hours then I don’t know what to solve ,this question is a complete

anybody know how to do this? if so, please explain!

Answers

Answer:

The x-intercepts are at (-4, 0) and (3, 0). The y-intercept is at (0, 1.2).

The graph is increasing at (-4, 0), (2.082, -0.604), (3, 0).

The graph is decreasing at (-2.082, 3.004), (0, 1.2), (1, 0)

Step-by-step explanation:

If Ahmad’s balance is $85, what will the minimum payment be?

Answers

$255 at 4 days and $850 at 1 week and I don’t know the month payment yet soo pls rate :)))

Farah is x years old. Ibtisam is 3 years younger than Farah. Muna is twice as old as Ibtisam. Write and expression in terms of x, for
(a) Ibtisam's age,
(b) The sum of their three ages, giving your answer in its simplest form.​

Answers

Answer:

Farah: x

Ibtisam: x-3

Muna: 2(x-3) or 2x-6

Sum of all their ages: 4x-6

Step-by-step explanation:

Farah is x, so we don't need an expression for that.

Ibtisam is 3 years younger than Farah, which means that we need to subtract 3 from Farah, and that would be Ibtisam's age. x-3.

Muna is 2 TIMES Ibtisam's age, so we need to multiply whatever expression taht was used for Ibtisam by 2. Put brackets around the equation with 2 outside: 2(x-3). Solve and you get 4x-6

Now, you have all their ages in expression form, now you need to simplify by adding:

x+x+2x-6

We cannot simplify -6, so we put that aside. Add all the x's and you get 4x, insert the minus 6 at the end:

4x-6

Hope this helps!

--Applepi101

Answer:

a) X -3

b) 4x - 9

Step-by-step explanation:

a) Farah's age is X so Ibtisam will be X - 3 old since he is 3years younger than Farah

b) Farah is X years old

Ibtisam is X - 3 years old

Muna is 2(X -3) since she is 2 times older than Ibtisam.

the sum of Thier ages will be

X + X -3 + 2(x-3)

= 2x - 3 + 2x - 6

= 4x - 9


Find the distance given the coordinates (-2, -1) & (-8, 7) in the simplest form
O 72
072
O 10
O 100

Answers

Answer:

O 10

Step-by-step explanation:

d = √((x2 - x1)² + (y2 - y1)²)

d = √((-8 - -2)² + (7 - -1)²)

d = √((-6)² + (8)²)

d = √(36) + (64)

d = √100

d = 10

PLEASE SHOW YOUR WORK! I NEED THIS QUICK! THANK YOU!! POINTS AND RATES WILL BE GIVEN!!

Answers

Answer:

3

Step-by-step explanation:

Y is given by sin(theta). sin(-60)=-sqrt(3)/2

Suppose A and B are events with P(A) = 1/4, P(B) = 1/3 and P(A cup B)= 1 2 a ) Find P(A cap B) b) Find P(A|B)

Answers

Answer:

Step-by-step explanation:

Parallelogram QRST has vertices Q(- 4, 2) . R(-2,4),5(0)) draw and label the image after a counterclockwise rotation of 270 degrees about the origia.please I need help.

Answers

Answer:

gr,wrgñegetjj

Step-by-step explanation:

jyyjytjjttj

Solve the equation on the interval [0,2pi) 7sec x-7=0

Answers

Answer:

2π or 0π are the only points that satisfy the expression, but since the restriction is 0 <= x < 2π

the answer would be 0π

The solution of the equation on the interval [0,2π) is 0.

To find Solution of the equation.

What is equation?

A statement that the values of two mathematical expressions are equal.

The given equation is :

7secx-7=0 on the interval [0,2π)

7secx-7=0

7secx=7

sec x =1

∴ x=0

So, the solution of the equation on the interval [0,2π) is 0.

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Write 2.71 repeating as a simplified fraction.

271/100 is wrong

Answers

Answer:

269/99

Step-by-step explanation:

Calculate the amount in an account after one year that starts
with the principal listed below and pays the specified annual
rate of interest compounded yearly.
Principal = $18,000, Rate = 3%

Answers

9514 1404 393

Answer:

  $18,540

Step-by-step explanation:

When interest is compounded yearly, the amount of interest earned in one year is the same as the amount of simple interest earned. The account balance is ...

  A = P(1 +r) = $18,000(1 +.03) = $18,540

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