1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Shalnov [3]
3 years ago
6

The water works commission needs to know the mean household usage of water by the residents of a small town in gallons per day.

They would like the estimate to have a maximum error of 0.14 gallons. A previous study found that for an average family the variance is 1.69 gallons and the mean is 15.9 gallons per day. If they are using a 85% level of confidence, how large of a sample is required to estimate the mean usage of water? Round your answer up to the next integer.
Mathematics
1 answer:
valina [46]3 years ago
7 0

Answer:

A sample of 179 is needed.

Step-by-step explanation:

We have that to find our \alpha level, that is the subtraction of 1 by the confidence interval divided by 2. So:

\alpha = \frac{1 - 0.85}{2} = 0.075

Now, we have to find z in the Ztable as such z has a pvalue of 1 - \alpha.

That is z with a pvalue of 1 - 0.075 = 0.925, so Z = 1.44.

Now, find the margin of error M as such

M = z\frac{\sigma}{\sqrt{n}}

In which \sigma is the standard deviation of the population and n is the size of the sample.

A previous study found that for an average family the variance is 1.69 gallon?

This means that \sigma = \sqrt{1.69} = 1.3

If they are using a 85% level of confidence, how large of a sample is required to estimate the mean usage of water?

A sample of n is needed, and n is found for M = 0.14. So

M = z\frac{\sigma}{\sqrt{n}}

0.14 = 1.44\frac{1.3}{\sqrt{n}}

0.14\sqrt{n} = 1.44*1.3

\sqrt{n} = \frac{1.44*1.3}{0.14}

(\sqrt{n})^2 = (\frac{1.44*1.3}{0.14})^2

n = 178.8

Rounding up

A sample of 179 is needed.

You might be interested in
Please help it is a interim test​
Levart [38]

Answer:

\pi

Step-by-step explanation:

5 0
3 years ago
Read 2 more answers
Match wash hypotenuse length with the leg lengths that will create a right triangle
Ugo [173]
Hope this can help you

5 0
3 years ago
Read 2 more answers
Sam is a painter. He has 2 1/4 gallons of paint, and it takes 3/4 of a gallon to paint a room. How many rooms can he paint?
Masteriza [31]
The answer is c . I hope I helped
5 0
3 years ago
Read 2 more answers
The manager of a store increases the price of the bathing suits by 7%. Let t be the original price of a bathing suit. The new pr
Dvinal [7]

Answer:

t+0.07t=t(1+0.07)=t(1.07)=1.07t

Step-by-step explanation:

There are a couple of  equivalent expressions to the function t+0.07t. For example:

t+0.07t

Factor:

t+0.07t=t(1+0.07)

If you add the terms inside the parentheses:

t(1+0.07)=t(1.07)

Basically you can add the like terms from the start and get the same result.

t+0.07t=1.07t

Therefore:

t+0.07t=t(1+0.07)=t(1.07)=1.07t

3 0
3 years ago
will be BRAINLIEST if answered fast What does finding a balance in the use of drones mean? Is FAA working to find a balance? why
wel
In this article, professor Hillary Farber talks about 'finding balance' in the use of drones by this she means that we need to find a way that we can use drones and have privacy and be safe. I believe that FAA is working to find a balance because they created new rules for the use of drones. Also, they created a national drone registry or list.
6 0
3 years ago
Other questions:
  • The equation d=4 -1/15t represents your distance from home,d, for each minute you walk,t. If you graphed this equation, determin
    14·2 answers
  • What is the hundred of 50,000?
    15·1 answer
  • Jane bought 4 books, 3 cups, and 7 rungs. She paid $4 per book, $5 per cup, and $10 per ring. Estimate her change from $50 bill
    9·2 answers
  • In a class of 120 student 70 student passes in english 80 student pass in hindi and 40 passes in both english and hindi how many
    11·1 answer
  • What root of x does the expression (x^3/8)^z/3 yield?
    13·2 answers
  • Please help 25 points and brainliest
    9·1 answer
  • If a perimeter is 20/21 what is the side length of the square
    15·2 answers
  • <img src="https://tex.z-dn.net/?f=%20-%20x%20-%203%20%2B%20x%20%3D%20%20%5Csqrt%7B9%20-%202x%7D%20%20%20%2B%20x" id="TexFormula1
    6·2 answers
  • Find the equation of the line that passes through (5, 12) and has a slope of -6
    5·1 answer
  • S+2m=20 s-5=m substitution
    5·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!