A telephone service representative believes that the proportion of customers completely satisfied with their local telephone service is different between the South and the Midwest. The representative's belief is based on the results of a survey. The survey included a random sample of 1300 southern residents and 1380 midwestern residents. 39% of the southern residents and 50% of the midwestern residents reported that they were completely satisfied with their local telephone service. Find the 80% confidence interval for the difference in two proportions. Step 1 of 3 : Find the point estimate that should be used in constructing the confidence interval

Answers

Answer 1

Answer:

The point estimate that should be used in constructing the confidence interval is 0.11.

The 80% confidence interval for the difference in two proportions is (0.0856, 0.1344).

Step-by-step explanation:

Before building the confidence interval, we need to understand the central limit theorem and subtraction of normal variables.

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 [tex]\mu[/tex] and standard deviation [tex]s = \frac{\sigma}{\sqrt{n}}[/tex].

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

For a proportion p in a sample of size n, the sampling distribution of the sample proportion will be approximately normal with mean [tex]\mu = p[/tex] and standard deviation [tex]s = \sqrt{\frac{p(1-p)}{n}}[/tex]

Subtraction between normal variables:

When two normal variables are subtracted, the mean is the difference of the means, while the standard deviation is the square root of the sum of the variances.

Midwest:

50% of 1380, so:

[tex]p_M = 0.5[/tex]

[tex]s_M = \sqrt{\frac{0.5*0.5}{1380}} = 0.0135[/tex]

South:

39% of 1300, so:

[tex]p_S = 0.39[/tex]

[tex]s_S = \sqrt{\frac{0.39*0.61}{1300}} = 0.0135[/tex]

Distribution of the difference:

[tex]p = p_M - p_S = 0.5 - 0.39 = 0.11[/tex]

So the point estimate that should be used in constructing the confidence interval is 0.11.

[tex]s = \sqrt{s_M^2+s_S^2} = \sqrt{0.0135^2+0.0135^2} = 0.0191[/tex]

Confidence interval:

[tex]p \pm zs[/tex]

In which

z is the z-score that has a p-value of [tex]1 - \frac{\alpha}{2}[/tex].

80% confidence level

So [tex]\alpha = 0.2[/tex], z is the value of Z that has a p-value of [tex]1 - \frac{0.2}{2} = 0.9[/tex], so [tex]Z = 1.28[/tex].  

The lower bound of the interval is:

[tex]p - zs = 0.11 - 1.28*0.0191 = 0.0856[/tex]

The upper bound of the interval is:

[tex]p + zs = 0.11 + 1.28*0.0191 = 0.1344[/tex]

The 80% confidence interval for the difference in two proportions is (0.0856, 0.1344).


Related Questions

the adjacent sides of a parallelogram are (x + 3) and (x + 2). Find the perimeter of the parallelogram

Answers

9514 1404 393

Answer:

  4x+10

Step-by-step explanation:

For parallelogram adjacent sides a and b, the perimeter is ...

  P = 2(a +b)

For the given sides, the perimeter is ...

  P = 2((x +3) +(x +2)) = 2(2x +5)

  P = 4x +10 . . . perimeter of the parallelogram

Which side of the polygon is exactly 6 units long?

Answers

Answer:

AB is correct as It is the shorter parallel line

as the line measures 6 units.

Step-by-step explanation:

The polygon is a trapezoid / (trapezium Eng/Europe)

We see the given coordinates  (2, 6) - (-4, 6) = x-6 y 0 = x = 6units

as x always is shown as x - 6  as  x= 6

We can also show workings as y2-y1/x2-x1 = 6-6/-4-2 0/-6

y = 0  x = 6 = 6 units as its horizontal line.

when y is 6-6 = 0 then we know the line is horizontal for y = 0.

The difference of the measures -4 to 2 is 6units so if no workings we just add on from -4 to 2 and find the answer is 6 units long.

When looking at diagonal lines we still group the x's and y's and make the fraction whole.

When looking for solid vertical lines that aren't shown here we use the y values if showing workings and show x =0 to cancel out.

2/3y = 1/4 what does y equal?

Answers

Answer:

Step-by-step explanation:

2/3y=1/4 this means 3y=8 then you divide both sides by 8 you will get the value of y =8/3

Which one goes where?

Answers

"RS tangent to circle a..." is first statement          Reason: Given

Second Reason: "Radius perpendicular to tangent"

Second Statement: "AR is parrallel to BS"      Reason: "2 lines perpendicular..."

PLEASE HELP WILL MARK BRAINLIEST

Answers

9514 1404 393

Answer:

  x = 10/3 = 3 1/3 ≈ 3.33

Step-by-step explanation:

Triangles ABC and ADE are similar, so corresponding sides are proportional.

  DE/DA = BC/BA

  x/(4+6) = 2/6

  x = 10(2/6) = 10/3 = 3 1/3

Cyril has six more than twice as many mangoes as Kubie and half as many mangoes as Maxine. If Kubie has six mangoes, then, in terms of x, how many mangoes do Cyril, Kubie, and Maxine have combined?​

Answers

Answer:

(7x + 18) or 60 Mangoes

Step-by-step explanation:

Let the no. of mangoes Kubie possesses be x

So,

Cyril has mangoes = 2x + 6  ...(i)

So,

Maxine has = 2 * (2x + 6)

= 4x + 12

Given that,

Kubie has mangoes = 6

∵ The combined mangoes they have in terms of x,

= Cyril + Kubie + Maxine

= (2x + 6) + x + (4x + 12)

= 7x + 18

A.T.Q.

Cyril has = 2x + 6

∵ Cyril has mangoes = 2 * (6) + 6

= 18 mangoes

∵ Maxine has = 2 * Cyril's mangoes

= 2 * 18

= 36

Thus,

Total mangoes = Cyril + Kubie + Maxine

= 18 + 6 + 36

= 60 Mangoes

y
27
х
10
11
12
In order for the data in the table to represent a linear
, function with a rate of change of -8, what must be the
value of a?
a
11
O a = 2
O a = 3
O a = 19
a = 35

Answers

It’s c for sure only because I had it on a test

The value of a that would make the data in the table represent a linear function with a rate of change of -8 is a = 19.

Option D is the correct answer.

What is a function?

A function has an input and an output.

A function can be one-to-one or onto one.

It simply indicated the relationships between the input and the output.

Example:

f(x) = 2x + 1

f(1) = 2 + 1 = 3

f(2) = 2 x 2 + 1 = 4 + 1 = 5

The outputs of the functions are 3 and 5

The inputs of the function are 1 and 2.

We have,

The rate of change of a linear function is also known as the slope of the function.

To determine the slope of the function represented by the given table, we need to calculate the change in Y for a unit change in X.

Using the values given in the table, we can calculate the slope as follows:

Slope = (Change in Y) / (Change in X)

So,

(a - 27) / (11 - 10) = (11 - 27) / (12 - 10) = -8

Setting this equation equal to -8, we get:

= (a - 27) / 1

= -8

Simplifying the equation, we get:

a - 27 = -8

a = 19

Therefore,

The value of a that would make the data in the table represent a linear function with a rate of change of -8 is a = 19.

Learn more about functions here:

https://brainly.com/question/28533782

#SPJ7

For -180°<θ<0 , which of the primary trigonometric functions may have positive values?

Answers

Answer:

cos theta  = adj / hyp is positive (+/+)

Step-by-step explanation:

In this open interval, the hypotenuse (radius) is always positive, whereas the adjacent side is positive and the opposite side negative.

in this interval:

sin theta = opp / hyp is neg (-/+)

cos theta  = adj / hyp is positive (+/+)

tan theta = opp / adj = (-/+) :  negative

what is the discrimination of the polynomial below ?
9x2-18x+9

Answers

Answer:

9(x - 1)^2

Step-by-step explanation

9x^2 - 18x + 9

Find the Greatest Common Factor (GCF) in the polynomial

Answer: 9

Then use it to discriminate the polynomial

9(x - 1)^2

E. The ratio of monthly income to savings of a family is 7:2. If the savings is Rs. 500, find the monthly income and expenditure.​

Answers

Step-by-step explanation:

Since the ratio of monthly income to savings of the family is 7:2, we assume that the income be 7t and savings be 2t

Now, we are given that the savings is =Rs 500

So, According to our assumption, 2t=500

⇒t=250

Hence, the income of the family is =7×250=Rs 1750

And the expenditure is =Income−Savings

=Rs 1750−Rs 500

=Rs 1250

Describe the transformation of f(x) to g(x). Pleaseee helllp thank youuuu!!!

Answers

The transformation set of [tex]y[/tex] values for function [tex]f[/tex] is [tex][-1,1][/tex] this is an interval to which sine function maps.

You can observe that the interval to which [tex]g[/tex] function maps equals to [tex][-2,0][/tex].

So let us take a look at the possible options.

Option A states that shifting [tex]f[/tex] up by [tex]\pi/2[/tex] would result in [tex]g[/tex] having an interval [tex][-1,1]+\frac{\pi}{2}\approx[0.57,2.57][/tex] which is clearly not true that means A is false.

Let's try option B. Shifting [tex]f[/tex] down by [tex]1[/tex] to get [tex]g[/tex] would mean that has a transformation interval of [tex][-1,1]-1=[-2,0][/tex]. This seems to fit our observation and it is correct.

So the answer would be B. If we shift [tex]f[/tex] down by one we get [tex]g[/tex], which means that [tex]f(x)=\sin(x)[/tex] and [tex]g(x)=f(x)-1=\sin(x)-1[/tex].

Hope this helps :)

Assuming that the sample mean carapace length is greater than 3.39 inches, what is the probability that the sample mean carapace length is more than 4.03 inches

Answers

Answer:

The answer is "".

Step-by-step explanation:

Please find the complete question in the attached file.

We select a sample size n from the confidence interval with the mean [tex]\mu[/tex]and default [tex]\sigma[/tex], then the mean take seriously given as the straight line with a z score given by the confidence interval

[tex]\mu=3.87\\\\\sigma=2.01\\\\n=110\\\\[/tex]

Using formula:

[tex]z=\frac{x-\mu}{\frac{\sigma}{\sqrt{n}}}[/tex]  

The probability that perhaps the mean shells length of the sample is over 4.03 pounds is

[tex]P(X>4.03)=P(z>\frac{4.03-3.87}{\frac{2.01}{\sqrt{110}}})=P(z>0.8349)[/tex]

Now, we utilize z to get the likelihood, and we use the Excel function for a more exact distribution

[tex]=\textup{NORM.S.DIST(0.8349,TRUE)}\\\\P(z<0.8349)=0.7981[/tex]

the required probability: [tex]P(z>0.8349)=1-P(z<0.8349)=1-0.7981=\boldsymbol{0.2019}[/tex]

By selling a radio for $8400 a dealer gained 12% .how much money did she gain​

Answers

Answer:

Amount gained = $900

Step-by-step explanation:

Let the cost price be = x

Given selling price = 8400

And profit% = 12%

Profit = selling price - cost price

        = 8400 - x

[tex]Profit \ \% = \frac{profit}{cost \ price} \times 100\\\\12\% = \frac{8400 - x}{x} \times 100\\\\\ 12 \times \frac{1}{100} = \frac{8400 - x}{x}\\\\\frac{12 \ x}{100} = 8400 - x \\\\\frac{12x}{100} + x = 8400\\\\12x + 100x = 8400 \times 100\\\\112x = 8400 \times 100\\\\x = \frac{8400 \times 100}{112} = 7500[/tex]

Therefore , cost price of the radio $7500

The amount she gained = 8400 - 7500 = $ 900

hope anyone help me please​

Answers

9514 1404 393

Answer:

  a) Lahulspiti: -8; Srinigar: -2; Shimla: 5; Ooty: 14; Bengahuru: 22

  b) 30

  c) 6

  d) yes; no

Step-by-step explanation:

a) The values are read from the graph.

__

b) 22 -(-8) = 22 +8 = 30 . . . . difference between highest and lowest

__

c) -2 -(-8) = -2 +8 = 6 . . . positive difference

(Technically, the difference between L and S is L - S = (-8) -(-2) = -6.)

__

d) -2 + 5 < 5 . . . . true

  -2 + 5 < -2 . . . . false

A consumer electronics company is comparing the brightness of two different types of picture tubes for use in its television sets. Tube type A has mean brightness of 100 and standard deviation of 16, and tube type B has unknown mean brightness, but the standard deviation is assumed to be identical to that for type A. A random sample of tubes of each type is selected, and is computed. If equals or exceeds , the manufacturer would like to adopt type B for use. The observed difference is . a. What is the probability that exceeds by 3.0 or more if and are equal

Answers

Answer:

The answer is "0.7794".

Step-by-step explanation:

Please find the complete question in the attached file.

Given:

[tex]\to n_{1}=n_{2}=25\\\\[/tex]

Hypotheses:

[tex]\to H_{0}:\mu_{B}-\mu_{A}\geq 0\\\\\to H_{a}:\mu_{B}-\mu_{A}< 0\\\\[/tex]

Testing statistics:

[tex]\to z=\frac{(\bar{x}_{B}-\bar{x}_{A})-(\mu_{B}-\mu_{A})}{\sqrt{\frac{\sigma^{2}_{B}}{n_{1}}+\frac{\sigma^{2}_{A}}{n_{2}}}}=\frac{3.5-(0)}{\sqrt{\frac{16^{2}}{25}+\frac{16^{2}}{25}}}=0.77[/tex]

The test is done just so the p-value of a test is

[tex]\to p-value = P(z < 0.77) = 0.7794[/tex]

Because the p-value of the management is large, type B can take it.

Chang has 2 shirts: a white one and a black one. He also has 2 pairs of pants, one blue and one tan. What is the probability, if Chang gets dressed in the dark, that
he winds up wearing the white shirt and tan pants? Show your work.

Answers

Answer:

1/4

Step-by-step explanation:

White = w

Black = B

Blue = b1

Tan = t

Wb1

Wt

Bbi

Bt

The answer will be 1/4, because there are 4 ways it can work and only 1 way it can be white shirt and tan pants.

Answer:

1/4

Step-by-step explanation:

it would be 1/4 because there are 4 different clothing pieces in total and there is only one way it would work the way the problem says.

Suppose a sample of 1453 new car buyers is drawn. Of those sampled, 363 preferred foreign over domestic cars. Using the data, estimate the proportion of new car buyers who prefer foreign cars. Enter your answer as a fraction or a decimal number rounded to three decimal places

Answers

Answer:

"0.250" is the appropriate answer.

Step-by-step explanation:

Given:

New car sample,

= 1453

Preferred foreign,

= 363

Now,

The amount of new automobile purchasers preferring foreign cars will be approximated as:

= [tex]\frac{363}{1453}[/tex]

= [tex]0.250[/tex]

The administration conducted a survey to determine the proportion of students who ride a bike to campus. Of the 123 students surveyed 5 ride a bike to campus. Which of the following is a reason the administration should not calculate a confidence interval to estimate the proportion of all students who ride a bike to campus. Which of the following is a reason the administration should not calculate a confidence interval to estimate the proportion of all students who ride a bike to campus? Check all that apply.

a. The sample needs to be random but we don’t know if it is.
b. The actual count of bike riders is too small.
c. The actual count of those who do not ride a bike to campus is too small.
d. n*^p is not greater than 10.
e. n*(1−^p)is not greater than 10.

Answers

Answer:

b. The actual count of bike riders is too small.

d. n*p is not greater than 10.

Step-by-step explanation:

Confidence interval for a proportion:

To be possible to build a confidence interval for a proportion, the sample needs to have at least 10 successes, that is, [tex]np \geq 10[/tex] and at least 10 failures, that is, [tex]n(1-p) \geq 10[/tex]

Of the 123 students surveyed 5 ride a bike to campus.

Less than 10 successes, that is:

The actual count of bike riders is too small, or [tex]np < 10[/tex], and thus, options b and d are correct.

As one once said Another one

Answers

Answer:

f

Step-by-step explanation:

Answer:

S = 62.9

Step-by-step explanation:

Since this is a right triangle, we can use trig functions

tan S = opp side / adj side

tan S = sqrt(42)/ sqrt (11)

tan S = sqrt(42/11)

Taking the inverse tan of each side

tan ^ -1( tan S) =  tan ^-1(sqrt(42/11))

S=62.89816

Rounding to the nearest tenth

S = 62.9

40% of what number is 16.6?

Answers

Answer: 41.5

hope this helps!

Create truth table to determine whether or not the following statements are logically equivalent

Answers

The statement is totally false.

[tex]\neg P\lor\neg Q \equiv \neg(P \land Q) \not\equiv P\land Q[/tex]

because (P and ¬P) is a contradiction.

Perimeter (numerical) cm

Answers

Answer:

101 cm

Step-by-step explanation:

Add all the side lengths up to get 101 cm.

An isosceles trapezoid has a consecutive-sides of length: 10,6,10 and 14. Find the measure of each angle if the trapezoid.

Answers

Answer:

Angle A = Angle D = 69° 30'

Angle B = Angle C = 110° 30'

Step-by-step explanation:

     B ___ C

    /              \

  /                  \

A ________ D

AB and CD are 10

BC is 6

AD is 14

If we divide the trapezoid, we can imagine a line.

     B_ F_C

    /      |      \

  /        |         \

A ___E____ D

AE = ED = 7 (14/2)

BF = FC = 3

So now, we draw another line from B or C to AE or ED

     B_ F_ C

    /      |     | \

  /        |     |    \

A ___E_ G_ D

EG = GD = 3.5 (7/2)

There is a right triangle now, GCD

GD is 3.5 and CD is 10. To determine angle D, we can apply trigonometric function:

CD is H, and GD is A

cos D = A/H

cos D = 3.5/10 → 0.35

angle D = 69° 30'

By theory, we know that angle D and angle A, are the same so:

Angle D = Angle A = 69° 30'

Angle B = Angle C

We also make a cuadrilateral, which is EFCD.

Angle D is 69° 30', Angle E is 90°, Angle F is also 90°

Sum of angles in cuadrilateral is 360°

360° - 69° 30' - 90° - 90° = Angle C = Angle B

Angle C = Angle B = 110° 30'

Let's confirm the angles in the trapezoid:

69° 30' + 110° 30' + 69° 30' + 110° 30' = 360°

A + B + C + D

Suppose point (4, −9) is translated according to the rule (, ) → ( + 3, − 2). What are the coordinates of ′? Explain

Answers

Answer: I’m sorry I just need points..

If $6^x = 5,$ find $6^{3x+2}$.

Answers

If 6ˣ = 5, then

(6ˣ)³ = 6³ˣ = 5³ = 125,

and

6³ˣ⁺² = 6³ˣ × 6² = 125 × 6² = 125 × 36 = 4500

khai niem hinh cat don gian ?

Answers

Answer:

khai niem hinh cat don gian?

find and sketch the domain of the function. f(x,y)=√(4-x^2-y^2) +√(1-x^2)

Answers

Answer:

Hello

Step-by-step explanation:

The domain is limited with 2 lines parallel: -1 ≤ x ≤ 1

and the disk ? (inside of a circle) of center (0,0) and radius 2

[tex]dom\ f(x,y)=\{(x,y) \in \mathbb{R} ^2 | \ -1\leq x \leq -1\ and \ ( -\sqrt{4-x^2} \leq \ y \leq \sqrt{4-x^2}\ ) \ \}\\[/tex]

a triangle has sides of 6 m 8 m and 11 m is it a right-angled triangle?​

Answers

Answer:

No

Step-by-step explanation:

If we use the Pythagorean theorem, we can find if it is a right triangle. To do that, set up an equation.

[tex]6^{2}+8^{2}=c^2[/tex]

If the triangle is a right triangle, c would equal 11

Solve.

[tex]36+64=100[/tex]

Then find the square root of 100.

The square root of 100 is 10, not 11.

So this is not a right triangle.

I hope this helps!

What is the explicit formula for the sequence ? -1,0,1,2,3

Answers

Answer:

B

Step-by-step explanation:

substitute the values in the eq. Ot is also arithmetic progression.

Determine the domain and range of the graph

Answers

Answer:

5 ≤ x ≤ 10             5 ≤ y ≥ -1

Step-by-step explanation:

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