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 0.12 gallons. A previous study found that for an average family the variance is 5.29 gallons and the mean is 17 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

Answers

Answer 1

Answer:

\(n=(\frac{1.440(2.3)}{0.12})^2 =761.76 \approx 762\)

So the answer for this case would be n=762 rounded up to the nearest integer

Step-by-step explanation:

Information given

\(\bar X = 17\) represent the mean

\(\mu\) population mean (variable of interest)

\(\sigma= \sqrt{5.29}= 2.3\) represent the standard deviation

Solution to the problem

The margin of error is given by this formula:

\( ME=z_{\alpha/2}\frac{s}{\sqrt{n}}\)    (a)

And on this case we have that ME =0.12 and we are interested in order to find the value of n, if we solve n from equation (a) we got:

\(n=(\frac{z_{\alpha/2} \sigma}{ME})^2\)   (b)

The confidence level is 85%, the significance level would be \( \alpha=1-0.85 = 0.15\) and \(\alpha/2 =0.075\) the critical value for this case would be \(z_{\alpha/2}=1.440\), replacing into formula (b) we got:

\(n=(\frac{1.440(2.3)}{0.12})^2 =761.76 \approx 762\)

So the answer for this case would be n=762 rounded up to the nearest integer


Related Questions

In a 30 degree, 60 degree, 90 degree triangle shortest side is 15. Find the lengths of the other sides. Will give brainliest for correct answer

Answers

Answer:

The ratio of sides in a 30-60-90 triangle is 1:√3:2. Since the shortest side is the 1 in this case the other lengths are 15√3 and 30.

A line segment with one end at A (-3,2) has midpoint M (2,-3). Find the coordinate of the other end point B.
(A.) B (-1,-1)
(B.) B (5,-5)
(C.) B (1,-4)
(D.) B (7,-8)

Answers

Answer:

D

Step-by-step explanation:

since all x coordinates are distinct, lets just find the x coordinate (multiple choice question)

Midpoint formula:

given two points, (x1, y1) and (x2, y2)

the midpoint is ((x1+x2)/2, (y1+y2)/2)

-3+x2 = 2*2

x2 = 7

Suppose that $6000 is placed in a savings account at an annual rate of 4%, compounded quarterly. Assuming that no withdrawals are made, how long will it take for the account to grow to $8670?

Answers

The time taken for the money to grow to $8670 at compound interest is approximately 9.24 years.

Given the amount of money that is the principal = $6000

Rate = 4% compounded quarterly.

Time = t

Amount = $8670

Now we know that the amount is calculated by the formula:

A = P(1+r/4)ⁿ

8670 = 6000(1+0.01)ⁿ

Hence

log 1.445 = n log 1.01

or, n = 36.99

Number of years = 36.99 / 4 = 9.24 years.

The interest that is added to a loan or deposit is referred to as compound interest. Compound interest is computed for a sum utilizing both the principal and interest already paid. The main distinction between compound interest and simple interest is this.

If we look at our bank statements, interest is usually credited to our account once a year. While the principle remains constant, the interest changes annually.

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Write the Standard Form of the line with x-intercept of 3 and y-intercept of 4.
4x + 3y = 12
3x + 4y = 12
3x + 4y = 7
4x + 3y = 7

Answers

4x + 3y= 12

4x + 3*0= 12, x-int= 3

4*0 + 3y= 12, y-int= 4

On field trips there must be 2 chaperones for every 15 students which ratio correctly express the ratio of students

Answers

Answer:

15:2 or 15 to 2

Step-by-step explanation:

They are asking for a ratio based on how many chaperones per student (in this case 15 students) In other words 15 students for every 2 chaperones.

Robert's book bag is weighing him down. His bag alone weighs 4 pounds. His library book
weighs 2 pounds. The math book is 4 times the weight of the library book, and his science
book is 2 times the weight of the math book. How much does his book bag weigh with all
these books? What is the heaviest book in his book bag?

Answers

The weight of Robert's bag alone is 4 pounds.

The library book weighs 2 pounds.

The math book is 4 times the weight of the library book, so it weighs 4 * 2 = 8 pounds.

The science book is 2 times the weight of the math book, so it weighs 2 * 8 = 16 pounds.

To find the total weight of Robert's book bag, we add the weights of all the books and the bag:

4 pounds (bag) + 2 pounds (library book) + 8 pounds (math book) + 16 pounds (science book) = 30 pounds.

Therefore, Robert's book bag weighs 30 pounds with all these books.

To determine the heaviest book in his book bag, we compare the weights of the books:

The bag weighs 4 pounds.
The library book weighs 2 pounds.
The math book weighs 8 pounds.
The science book weighs 16 pounds.
From these options, the science book is the heaviest, weighing 16 pounds.

Answer:

1) 30 pounds is the weight of the bag all together

2) science book is the heaviest book

Step-by-step explanation:

bag=4 pounds

library book=2 pounds

maths book=2×4=8 pounds

science book=8×2=16 pounds

4+2+8+16=30 pounds all together

heaviest book= science book (16 pounds)

In A container, there are red, blue and green balls. 3/11 of ball s are red There are 35 more blue balls than red balls. The remaining 90 balls are green. How many more blue balls than green balls are there? of the balls are red.​

Answers

If 3/11 of the balls are red, then (3/11) * 110 = 30 balls are red.

It is mentioned that there are 35 more blue balls than red balls. Therefore, the number of blue balls is 30 + 35 = 65.

The remaining balls are green, so the number of green balls is 110 - (30 + 65) = 15.

To find out how many more blue balls there are than green balls, we subtract the number of green balls from the number of blue balls: 65 - 15 = 50.

Therefore, there are 50 more blue balls than green balls.

What is 1+ 25372 +62719+ 82837?

Answers

Answer:

170929

Step-by-step explanation:

116,929 anyways thank for points

I need help with this

I need help with this

Answers

Answer:

Step-by-step explanation:

It was confusing

I need help with this

There are 40 children watching a magic show. 24 of the children are boys, and 16 of the children are girls. The magician needs to select 4 children to help him with his show. What is the probability that all 4 helpers will be girls

Answers

Answer:

1.99%. (2% rounded)

Step-by-step explanation:

The total number of ways to select 4 children out of 40 is given by the combination formula:

C(40,4) = 40! / (4! * (40-4)!) = 91,390

The number of ways to select 4 girls out of 16 is given by the combination formula as well:

C(16,4) = 16! / (4! * (16-4)!) = 1,820

Therefore, the probability of selecting 4 girls out of the group of 40 children is:

P(4 girls) = C(16,4) / C(40,4) = 1,820 / 91,390 ≈ 0.0199 or 1.99%

So the probability that all 4 helpers will be girls is approximately 1.99%

Hope this helps!.

how many cookies will Tina have if she bakes 7 more batches more than the maximum number of batches in the table

Cookies baked (y) is a function of number of batches (x).
Number of batches___total number of cookies
5__180
6__198
7__216
8__234
9__252​

Answers

Answer:

5

Step-by-step explanation:

the respone times for a certain ambulance company are normally distributed with a mean of 13 minutes.95% of the response times are between 10 and 16 minutes

Answers

The standard deviation of the response time is 1.53 minutes.

What is the standard deviation of the response time?

To get standard deviation, we will determine z-scores corresponding to the given percentiles and use them to calculate the standard deviation.

Z-score = z = (x - μ) / σ

For the lower bound of 10 minutes:

z = (10 - 13) / σ

For the upper bound of 16 minutes:

z = (16 - 13) / σ

As normal distribution is symmetric, the z-score corresponding to the lower tail of 2.5% is -1.96, and the z-score corresponding to the upper tail of 2.5% is 1.96.

Using z-scores, we set up  equations:

(10 - 13) / σ = -1.96

(16 - 13) / σ = 1.96

Solving the first equation:

-3 / σ = -1.96

σ = -3 / -1.96

Solving the second equation:

3 / σ = 1.96

σ = 3 / 1.96

Dividing both sides by 1.96:

-3 / 1.96 = σ

1.53 = σ

Full question:

The respone times for a certain ambulance company are normally distributed with a mean of 13 minutes.95% of the response times are between 10 and 16 minutes. What is S.D. of the response time.

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Which of the following sets of ordered pairs represents a function? PLEASE HELP

Which of the following sets of ordered pairs represents a function? PLEASE HELP

Answers

The set of ordered pairs that represents a function is (D) {(-6, -3), (-4, -3), (-3, -3), (-2, -3), (0, 0)}.

A set of ordered pairs represents a function if each unique input (x-value) is associated with only one output (y-value).

{(-4, -3), (-2, -1), (-2, 0), (0, -2), (0, 2)}

In this set, both (-2, -1) and (-2, 0) have the same x-value but different y-values. Therefore, this set does not represent a function.

{(-5, -5), (-5, -4), (-5, -3), (-5, -2), (-3,0)}

In this set, all the ordered pairs have the same x-value (-5). Since (-5, -5), (-5, -4), (-5, -3), and (-5, -2) have the same x-value but different y-values, this set does not represent a function.

{(-4, -5), (-4, 0), (-3, -4), (0, -3), (3, -2)}

In this set, (-4, -5) and (-4, 0) have the same x-value but different y-values. Therefore, this set does not represent a function.

{(-6, -3), (-4, -3), (-3, -3), (-2, -3), (0, 0)}

In this set, each unique x-value is associated with a single y-value. There are no repeated x-values. Therefore, this set represents a function.

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A used car dealer has the following information for two months of sales:Month 1: 239 cars soldMonth 2: 324 cars soldWhat is the increase/decrease of change?Round to the nearest percent.

Answers

Answer:

36%

Explanation:

The sales of cars in the two months are:

• Month 1: 239 cars sold

,

• Month 2: 324 cars sold

First, we determine if it is an increase or decrease.

If:

• Final - Initial = Positive (We have an increase)

,

• Final - Initial = Negative (We have a decrease)

In this case:

• Final Value = 324

,

• Initial Value =239

Final - Initial =324-239=85 (Positive)

\(\begin{gathered} \%\text{ Increase =}\frac{Final-\text{Initial}}{\text{Initial}}\times100 \\ =\frac{324-\text{2}39}{\text{2}39}\times100 \\ =\frac{85}{\text{2}39}\times100 \\ =35.56\% \\ =36\%\text{ (to the nearest percent)} \end{gathered}\)

The percentage increase in car sales is 36% to the nearest percent.

mike moved 345 chairs and gavin moved c more than mike. How many chairs did Gavin move in terms of c?

Answers

Answer:

345 + C

Step-by-step explanation:

From the first sentence, we know that Mike moved a total of:

           345chairs

In the second sentence, we know that Gavin moved C more chairs than Mike;

 Mathematically;

Number of chairs moved by Galvin;

                    345 + C

Therefore, in terms of C, the number of chairs moved by Gavin is:

              345 + C

Clea estimates that a glass contains 250.55 mL of water. The actual amount of water in the glass is 279.48 mL. HELP PLEASE

Answers

Answer:

the answer is 28.23

Step-by-step explanation:

just subtract them to know the difference between the estimate and the actual

Use Stokes´ Theorem to evaluate ∬s.curl F•nds. Assume that the Surface S is oriented upward.

F= (6yz)i+(5x)j+ (yz(e^(x^2)))k. ; S that portion of the paraboloid z=(1/4)x^2+y^2 for 0≤z≤4

Answers

The surface integral in terms of ρ and θ ∫∫S.((6y - 5)e^(x^2))

To evaluate ∬s.curl F•nds using Stokes' Theorem, we first need to find the curl of the vector field F and then compute the surface integral over the given surface S.

Given vector field F = (6yz)i + (5x)j + (yz(e^(x^2)))k, let's find its curl:

∇ × F = ∂/∂x (yz(e^(x^2))) - ∂/∂y (5x) + ∂/∂z (6yz)

Taking the partial derivatives, we get:

∇ × F = (0 - 0) i + (0 - 0) j + (6y - 5)e^(x^2)

Now, let's parametrize the surface S, which is the portion of the paraboloid z = (1/4)x^2 + y^2 for 0 ≤ z ≤ 4. We can use cylindrical coordinates for this parametrization:

r(θ, ρ) = ρcos(θ)i + ρsin(θ)j + ((1/4)(ρcos(θ))^2 + (ρsin(θ))^2)k

where 0 ≤ θ ≤ 2π and 0 ≤ ρ ≤ 2.

Next, we need to find the normal vector n to the surface S. Since S is oriented upward, the normal vector points in the positive z-direction. We can normalize this vector to have unit length:

n = (∂r/∂θ) × (∂r/∂ρ)

Calculating the partial derivatives and taking the cross product, we have:

∂r/∂θ = -ρsin(θ)i + ρcos(θ)j

∂r/∂ρ = cos(θ)i + sin(θ)j + (1/2)(ρcos(θ))k

∂r/∂θ × ∂r/∂ρ = (-ρsin(θ)i + ρcos(θ)j) × (cos(θ)i + sin(θ)j + (1/2)(ρcos(θ))k)

Expanding the cross product, we get:

∂r/∂θ × ∂r/∂ρ = (ρcos(θ)(1/2)(ρcos(θ)) - (1/2)(ρcos(θ))(-ρsin(θ)))i

+ ((1/2)(ρcos(θ))sin(θ) - ρsin(θ)(1/2)(ρcos(θ)))j

+ (-ρsin(θ)cos(θ) + ρsin(θ)cos(θ))k

Simplifying further:

∂r/∂θ × ∂r/∂ρ = ρ^2cos(θ)i + ρ^2sin(θ)j

Now, we can calculate the surface integral using Stokes' Theorem:

∬s.curl F•nds = ∮c.F•dr

= ∫∫S.((∇ × F)•n) dS

Substituting the values we obtained earlier:

∫∫S.((∇ × F)•n) dS = ∫∫S.((6y - 5)e^(x^2))•(ρ^2cos(θ)i + ρ^2sin(θ)j) dS

We can now rewrite the surface integral in terms of ρ and θ:

∫∫S.((6y - 5)e^(x^2))

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What is the value of (-4)-3?
1
64
О.

1
12
64
ОО
1
12

What is the value of (-4)-3?164.11264112

Answers

Answer:

Answer is -1/64

Step-by-step explanation:

Mark me the brilliant

The radius of a circle is 14 inches. What is the circle's area?
r=14 in
Use 3.14 for ​. (pls help me)

Answers

Answer:

153.86 inches²

Step-by-step explanation:

How do we find the radius of a circle?

The radius of a circle is 1/2 of the diameter, so 14/2 = 7 inches

How do we find the area of a circle?

We can find the area of a circle by using πr², where r = radius. We're given the radius as 7 inches and pi as 3.14.

Solving

\(3.14*7^2\)\(3.14*49\)\(153.86\)

Therefore, the answer is 153.86 inches².

Have a lovely rest of your day/night, and good luck with your assignments! ♡

A cylindrical pottery vase has a diameter of 4.3 inches and a height of 11 inches. What is the surface area of the vase? Use the formula SA = B + Ph, since the vase has a bottom but no top. Use 3.14 for π
and round to the nearest tenth of a square inch.

Answers

The surface area of the cylindrical pottery vase is 177.55 in².

Given that a cylindrical pottery vase has a diameter of 4.3 inches and a height of 11 inches, we need to find the surface area of the vase,

SA of a cylinder = 2π×radius(h+r)

= 2×3.14×2.15(2.15+11)

= 177.55 in²

Hence, the surface area of the cylindrical pottery vase is 177.55 in².

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What is the percent of the shaded portion of the
figure??
60%
80%
20 %
.60%
HELP MEEE PLSSSSSSSS

What is the percent of the shaded portion of thefigure??60%80%20 %.60%HELP MEEE PLSSSSSSSS

Answers

60%



((sorry if I got it wrong))

What is the fractional form of 0.8?
A. 8/10
B. 1/8
C. 8/9
D. 8/11

Answers

Answer:

(A.)  8/10

Step-by-step explanation:

This is because 8/10 is the same as 0.8 in fraction form. 0.8 is basically 8/10 of a whole number (the number being 1). See the picture for further explanation.

Think of fractions like a pizza. It's one whole pizza but when people eat from it, it's not whole anymore, let's say I had a pizza cut into ten slices. and someone ate 2 slices. Well now I have 8 slices! or you could call that, 8/10 (eight tenths) of a pizza. (or 0.8 precent of a pizza)

I Hope this helps! (Can you mark me Brainliest Please :>)

What is the fractional form of 0.8?A. 8/10B. 1/8C. 8/9D. 8/11

Find the distance between the points (6, 4) and (10, 7).

Answers

Answer:

5 units

Step-by-step explanation:

Use the distance formula \(d=\sqrt{(y_2-y_1)^2+(x_2-x_1)^2\) where \(d\) is the distance between points \((x_1,y_1)\) and \((x_2,y_2)\).

Given that \((x_1,y_1)\rightarrow(6,4)\) and \((x_2,y_2)\rightarrow(10,7)\), then:

\(d=\sqrt{(y_2-y_1)^2+(x_2-x_1)^2}\\\\d=\sqrt{(7-4)^2+(10-6)^2}\\\\d=\sqrt{3^2+4^2}\\\\d=\sqrt{9+16}\\\\d=\sqrt{25}\\\\d=5\)

This means that the distance between (6,4) and (10,7) is 5 units

what is negative 2/7 + 1/4 =

Answers

Answer:

-0.03571428571

Step-by-step explanation:

17.
Peter transports metal bars in his van.
The van has a safety notice: "Maximum Load 1200 kg".
Each metal bar has a label: "Weight 60 kg".
For safety reasons, Peter assumes that:
1200 is rounded correct to 2 significant figures, and
60 is rounded correct to 1 significant figure.
Calculate the greatest number of bars that Peter can safely put into the van if his assumptions are
correct.

Answers

Answer:

  17 bars

Step-by-step explanation:

Peter wants to compute the maximum number of bars he can load safely if the load limit of 1200 kg and the bar weight of 60 kg are each rounded to the number of significant digits those numbers have.

Range of values

The error in a rounded number is assumed to be as much as half of the least significant digit of the number.

Peter's load limit may actually be as low as ...

  1200 kg - (1/2)(100 kg) = 1150 kg . . . . . . . 1200 is rounded to nearest 100

Peter's bar weight might be as high as ...

  60 kg + (1/2)(10 kg) = 65 kg . . . . . . . . . . . 60 is rounded to nearest 10

Safe loading

If Peter has maximum-weight bars and does not want to exceed the minimum his load limit might be, the number of bars he can load is ...

  (1150 kg) / (65 kg/bar) ≈ 17.7 bars

The greatest number of bars Peter can load safely is 17.

75 points Dilations of Segments and Angles


CD is dilated by a scale factor of 3/4 ​ to form C ′ D ′ . CD measures 2. What is the measure of C ′ D ′ ?

Answers

Answer

0.823742

Step-by-step explanation:

just a genius

Mathematics

Find the rate

What percent of 200 is 50?
What percent of 50 is 40?
What percent of 10 is 6?
200 is what percent of 200?
What percent of 800 is 200?

Show your solution, HELP PLS ASAP!!!

I'LL GIVE 20 POINTS!!

Answers

Answer:

Step-by-step explanation:

25%

80%

60%

100%

25%

need help my dad owns this app

need help my dad owns this app

Answers

The volume of the solid is given as follows:

55 ft³.

How to obtain the volume of a rectangular prism?

The volume of a rectangular prism, with dimensions length, width and height, is given by the multiplication of these dimensions, according to the equation presented as follows:

Volume = length x width x height.

The total volume would be given as follows:

V = 9 x 6 x 1.25

V = 67.5 ft³.

The volume of the removed part is given as follows:

V = 1.25 x 2.5 x (9 - 3 - 2)

V = 12.5 ft³.

Hence the volume of the solid is given as follows:

67.5 - 12.5 = 55 ft³.

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Let Q be an orthogonal matrix with an eigenvalue λ1=1. Let x be an eighenvector beloinging to λ1. Show that x is also an eigenvector of QT

Answers

If Q is an orthogonal matrix with an eigenvalue λ1 = 1, then x, the eigenvector corresponding to λ1, is also an eigenvector of QT with an eigenvalue λ2 = λ1 * (QT * x).

To show that x is also an eigenvector of QT, we need to demonstrate that QT * x is a scalar multiple of x.

Given that Q is an orthogonal matrix, we know that QT * Q = I, where I is the identity matrix. This implies that Q * QT = I as well.

Let's denote x as the eigenvector corresponding to the eigenvalue λ1 This means that Q * x = λ1 * x.

Now, let's consider QT * x. We can multiply both sides of the equation Q * x = λ1 * x by QT:

QT * (Q * x) = QT * (λ1 * x)

Applying the associative property of matrix multiplication, we have:

(QT * Q) * x = λ1 * (QT * x)

Using the fact that Q * QT = I, we can simplify further:

I * x = λ1 * (QT * x)

Since I * x equals x, we have:

x = λ1 * (QT * x)

Now, notice that λ1 * (QT * x) is a scalar multiple of x, where the scalar is λ1. Therefore, we can rewrite the equation as:

x = λ2 * x

where λ2 = λ1 * (QT * x).

This shows that x is indeed an eigenvector of QT, with the eigenvalue λ2 = λ1 * (QT * x).

In conclusion, if Q is an orthogonal matrix with an eigenvalue λ1 = 1, then x, the eigenvector corresponding to λ1, is also an eigenvector of QT with an eigenvalue λ2 = λ1 * (QT * x).

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If a =5i + mj - 2k and b=10i+63-4k, find
a) axb
b) The value of mif a and bare parallel to one another.​

Answers

Answer:

B

um belo dia abençoado

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