The water works commission needs to know the mean household usage of water by the residents of a small town in gallons per day. Assume that the population standard deviation is 2.2 gallons. The mean water usage per family was found to be 15.8 gallons per day for a sample of 669 families. Construct the 90% confidence interval for the mean usage of water. Round your answers to one decimal place.

Answers

Answer 1

Answer:

The 90% confidence interval is   [tex]15.66< \mu < 15.94 [/tex]

Step-by-step explanation:

From the question we are told that

  The population standard deviation is  [tex]\sigma = 2.2[/tex]

  The  sample mean is  [tex]\= x = 15.8 \ gallon[/tex]

   The sample size is  n  =  669

   

From the question we are told the confidence level is  95% , hence the level of significance is    

      [tex]\alpha = (100 - 90 ) \%[/tex]

=>   [tex]\alpha = 0.10[/tex]

Generally from the normal distribution table the critical value  of  [tex]\frac{\alpha }{2}[/tex] is  

   [tex]Z_{\frac{\alpha }{2} } =  1.645[/tex]

Generally the margin of error is mathematically represented as  

      [tex]E = Z_{\frac{\alpha }{2} } *  \frac{\sigma }{\sqrt{n} }[/tex]

=>  [tex]E = 1.645  *  \frac{ 2.2}{\sqrt{669} }[/tex]

=>  [tex]E = 0.1399[/tex]

Generally 90% confidence interval is mathematically represented as  

      [tex]\= x -E <  \mu <  \=x  +E[/tex]

=>    [tex]15.8  - 0.1399 <\mu<  15.8  + 0.1399 [/tex]

=>    [tex]15.66< \mu < 15.94 [/tex]


Related Questions

What is 13 5/8 - 3 2/3?

Answers

Your answer is 9 23/24 and if your able to simply that’s all

In a watch, the minute hand crosses the hour hand for the third
time exactly after every 3 hr 18 min and 15 s of watch time. What
is the time gained or lost by this watch in one day?

Answers

The answer is 13 min and 50 seconds lost

What is 3 ÷ 2/5??



The quotient is 7 and ???

Answers

Answer:

7 and 5

Step-by-step explanation:

3 divided by 2/25 will be 15/2 in fraction form, and will be 7.5 in decimal form.

Answer:

The quotient is 7 1/2.

////////////////////////////

Answers

//////////////////////////

Answer:

///////////////////

Step-by-step explanation:

Jamal buys 33 bolts that cost $0.38 each,hich equation represents the best estimate for the total cost of all of the bolts

Answers

Answer:

12.54

Step-by-step explanation:

3 ÷ 6/7 i really need help! i will give you brainliest pls HELP​

Answers

Answer:

7/2

Step-by-step explanation:

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

3.5

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Which value is a solution to the inequality 2x − 5 < −12?

Question 21 options:

0


−4


−2


3

Answers

the correct answer would be -4

explanation:
2x-5<-12, add 5 to both sides so then you get 2x<-8, then divide by two, x<-4.

PLEASE HELP ASAP
IT AN EMERGENCY



Answers

Answer: E) Not enough information

We're given two pairs of congruent sides, and a pair of congruent angles. The angles are not between the two congruent sides. So we don't have enough information to know if the triangles are congruent or not. SSA is not a valid congruence theorem. This is because there are some cases where two triangles are possible leading to ambiguity.

If the marked angles were between the tickmarked sides, then we could use SAS.

ill mark brainleist
A department store sells logo shirts at an original price of $20. Every month that a shirt doesn’t sell, the store reduces the selling price by 25%. The store employees get a 50% markdown off the current price. Macy works at the store and sees the shirts going into the second markdown month. She decides that since 25% + 25% + 50% = 100%, the shirts must be free to employees. What is Macy’s error?

Answers

Answer:

25%

Step-by-step explanation:

Macy’s error is that the store employees get a 25% markdown off the current price. In the first markdown (i.e 50%) should have been reduced to 25% in the second markdown, instead of being totally free.


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-7
-3
1
5
9
13
-
- 12
yl -28
4
20
36
52
С C
10
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Answers

34555555555555555555555555555555555555

Which fraction is not equivalent to 9/12

Answers

Answer:

the second one :)

Step-by-step explanation:

Answer:

16/24

Step-by-step explanation:

Question 9/12 is equivalent to 3/4

15/20 is equivalent to 3/4

24/32 is equivalent to 3/4

6/8 is equivalent to 3/4

But 16/24 is equivalent to 2/3, not 3/4.

How do you solve substitution to the equation y=-2x +1 4x+y=9

Answers

Answer:

Step-by-step explanation:   2x+y=1

                                               4x+y=9        

we substract equals. 2x=8 so x=4 , y=-7

Taylor buys dog food for $1.25 a pound. How much will he pay for 8.6 pounds of dog?

Answers

Answer:

Taylor will pay $10.75

Step-by-step explanation:

If 1.25 PER/for each/for one pound that means you would multiply. So the equation is 8.6 x 1.25 = 10.75

Hope that helps and have a great day!

Answer:

10.75

Step-by-step explanation: 1.25 times 8.6 is 10.75 so that is the answer.

In a multiple linear regression analysis, statistical model utility is determined by the value of R2 and 2s, while practical model utility is determined by the Global F-test p-value.
a) true
b) false

Answers

Answer:

This statement is true because if F statistics is significant, then the entire multiple regression model is useful for the prediction of y.

Step-by-step explanation:

Solution:

In a multiple linear regression analysis, the statistical model utility is determined by the value of R2 and ∂2, while the Global F test p-value determines the practical model.

This statement is true because if F statistics is significant, then the entire multiple regression model is useful for the prediction of y.

The F test is a statistical test that is very flexible. F test can evaluate multiple model terms.

The F test indicates whether a linear regression model provides a better fit to data than a model that contains no independent variable.

The F test for overall significance has two hypotheses:

1- Null hypothesis:

                              The fit of the intercept only model and your model are equal.

2- Alternative hypothesis:

                               The fit of the intercept-only model is significantly reduced compared to your model.

Compare p-value for the F test,

If the p-value is less than the significance level, the sample data provide sufficient evidence  that the regression model fits the data better with no independent variable.

Will you do the same thing these students did? What are the other ways that you can help less fortunate people?​

Answers

ummmmmmmmmmmmmm huhhhhhh

If 4 adult elephants eat 320 pounds of food, how many ounces of food should the zookeeper purchase?

Answers

Answer:

Step-by-step explanation:


The signal from a certain satellite takes 0.06384 seconds to reach Earth. Estimate using scientific notation:

Answers

Answer: -63E2

Step-by-step explanation: i think

A ball is thrown vertically upwards with an initial velocity of 22 m/s. When will its speed be 10
m/s?

Answers

Answer:

The ball's speed will be 10 m/s at t=1.22 seconds

Step-by-step explanation:

The vertical motion of an object is controlled by the force of gravity. This means that there is a non-zero net force acting on the object that makes it accelerate downwards.

If the object is thrown upwards at speed vo, its speed at time t is:

[tex]v_f=v_o-g.t[/tex]

Where g is the acceleration of gravity [tex]g=9.8 m/s^2.[/tex]

Our ball is thrown upwards with v0=22 m/s. We need to calculate the time when its speed is vf=10 m/s.

Solving the above equation for t:

[tex]\displaystyle t=\frac{v_o-v_f}{g}[/tex]

Substituting:

[tex]\displaystyle t=\frac{22-10}{9.8}=\frac{12}{9.8}[/tex]

t=1.22 seconds

The ball's speed will be 10 m/s at t=1.22 seconds

Write an inequality for the following statement.
5 is less than or equal to y

Answers

Hiiii!!! It’s 5 ≤ y

Answer:

5 ≤ y

Step-by-step explanation:

Please Answer ASAP!!​

Answers

Answer:

0.17

Step-by-step explanation:

hope i helped

The director of the library believes that 13% of the library's collection is checked out. If the director is right, what is the probability that the proportion of books checked out in a sample of 774 books would be less than 10%

Answers

Answer:

The probability that the proportion of books checked out in a sample of 774 books would be less than 10% is 0.0066

Step-by-step explanation:

We are given that The director of the library believes that 13% of the library's collection is checked out.

[tex]\mu = p = 0.13[/tex]

Total no. of books = 774

Standard deviation =[tex]\sqrt{\frac{p(1-p)}{n}}[/tex]

Standard deviation = [tex]\sqrt{\frac{0.13(1-0.13)}{774}}=0.012[/tex]

We are supposed to find  the probability that the proportion of books checked out in a sample of 774 books would be less than 10%

[tex]P(\hat{p}<0.1)\\Z=\frac{x-\mu}{\sigma}\\Z=\frac{0.1-0.13}{0.012}\\Z=-2.48\\P(Z<-2.48)=0.0066[/tex]

So,[tex]P(\hat{p}<0.1)=0.0066[/tex]

Hence  the probability that the proportion of books checked out in a sample of 774 books would be less than 10% is 0.0066

The base of an aquarium with given volume V is made of slate and the sides are made of glass. If slate costs nine times as much (per unit area) as glass, find the dimensions of the aquarium that minimize the cost of the materials. (Let x, y, and z be the dimensions of the aquarium. Enter your answer in terms of V.) (x, y, z)

Answers

Answer:

The dimensions of the aquarium that minimize the cost of the materials:

[tex]x=y = \sqrt[3]{\frac{2V}{9}} , z = \sqrt[3]{\frac{81V}{4}}[/tex]

Step-by-step explanation:

Let x, y and z be the dimensions of aquarium .

Surface area of an aquarium = xy+2yz+2xz

Volume of aquarium V= [tex]Length \times Breadth \times Height =xyz----A[/tex]

We are given that slate costs five times as much (per unit area) as glass

So, Cost function : C=9xy+2yz+2xz

Now we will use langrage multiplier to find the dimensions of the aquarium that minimize the cost of the materials.

[tex]\nabla C = \lamda \nabla V\\(\frac{\partial C}{\patial x},\frac{\partial C}{\partial y}, \frac{\partial C}{\partial z})=\lambda(\frac{\partial V}{\patial x},\frac{\partial V}{\partial y}, \frac{\partial V}{\partial z})\\(9y+2z,9x+2z,2y+2x)=\lambda(yz+zx+xy)[/tex]

So,[tex]9y+2z=\lambda yz -----1\\9x+2z=\lambda zx -------2\\2y+2x=\lambda xy --------3[/tex]

Multiply 1 ,2 and 3 by x,y and z respectively.

[tex]9xy+2xz=\lambda xyz ------4\\9xy+2zy=\lambda zxy -------5\\2yz+2xz=\lambda xyz --------6[/tex]

Now equate 4 and 5

9xy+2xz=9xy+2yz

x=y

Substitute y=x in 5 and 6 and equate them

[tex]9x^2+2xz=2xz+2xz\\9x=2z\\\frac{9x}{2}=z[/tex]

Substitute the values in A

[tex]Volume = xyz=(x)(x)(\frac{9x}{2})\\Volume V = \frac{9x}{2}x^3\\\sqrt[3]{\frac{2V}{9}}=x\\x=y=\sqrt[3]{\frac{2V}{9}}\\z=\frac{9(\sqrt[3]{\frac{2V}{9}})}{2}\\z=\sqrt[3]{\frac{81V}{4}}[/tex]

Hence,

The dimensions of the aquarium that minimize the cost of the materials:

[tex]x=y = \sqrt[3]{\frac{2V}{9}} , z = \sqrt[3]{\frac{81V}{4}}[/tex]

Determine the x- and y-intercepts of the graph of x−4y=8 . HURRY!!!

Answers

the answer in point-slope form is y = 1/4x-2 so your y-intercept is -2 and from there, move up one and right four. your points would be (0, -2) and (4, -1)

hope this helped! :)

Pretest 5. In a group of 250 students, 40 are seniors. What percentage of the group are seniors?​

Answers

Answer:

[tex]\%seniors = 16\%[/tex]

Step-by-step explanation:

Given

[tex]Students = 250[/tex]

[tex]Seniors = 40[/tex]

Required

Determine the percentage of seniors

This is calculated as thus;

[tex]\%seniors = \frac{Seniors}{Students} * 100\%[/tex]

[tex]\%seniors = \frac{40}{250} * 100\%[/tex]

[tex]\%seniors = \frac{4000\%}{250}[/tex]

[tex]\%seniors = 16\%[/tex]

Help please I need the answer ASAP

Answers

Answer:

j

Step-by-step explanation:

I really need help i will mark u as brainliest

Answers

Answer:

1.23

Step-by-step explanation:

103.32/(7*12)

103.32/84

1.23

How can you represent a rate with 100 as the whole?

Please need help

Answers

Answer:

How to Calculate a Rate. "Rate" simply means the number of things per some other number, usually 100 or 1,000 or some other multiple of 10. A percentage is a rate per 100. Infant mortality rates are calculated per 1,000.

Step-by-step explanation:

who ever answers first i will give brainily!!!!

Answers

Answer:

85

Step-by-step explanation:

Answer:

30$*3=90$ - its the answer

Step-by-step explanation:

To get the answer we can first divide 60 by 2 to see how much cost 5 burgers. Then we have to multiply that result times 3 to get the answer.

60:2=30$ ----- 5 burgers.

30$*3=90$ - its the answer

3 step equations, I really need help on these with all the work:

1.
4x+y+5z=-9
x-4y-2z=-2
2x+3y-2z=21

2.
x-7y+3z=17
5x+2y-2z=-57
3x-10y-z=-11

Answers

Answer:

fdsfskdfdsjg,dgkdfjkgjkdfgjkfjkdghdkj

Step-by-step explanation:

PLZ HELP FAST
Enter an algebraic expression to model the given context. Give your answer in simplest form. The original price p of an item less a discount of 10%. The algebraic expression is​

Answers

Answer:

The algebraic expression is​ 0.90p

Step-by-step explanation:

The presentation of the algebraic expression is​ shown below:

Let us assume that the original price is p.

So,

The Orginal price is P

and the item would be less a 10% discount

So it could be written as 0.10p

Now the required expression could be written as

p - 0.10 p = 0.90p

Hence the algebraic expression is​ 0.90p

The same is to be considered

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