A telephone service representative believes that the proportion of customers completely satisfied with their local telephone service is different between the Midwest and the Northeast. The representative's belief is based on the results of a survey. The survey included a random sample of 1400 midwestern residents and 1320 northeastern residents. 50% of the midwestern residents and 38% of the northeastern residents reported that they were completely satisfied with their local telephone service. Find the 98% confidence interval for the difference in two proportions. Step 1 of 3 : Find the critical value that should be used in constructing the confidence interval.

Answers

Answer 1

Answer:

(0.1361 ; 0.2239)

Step-by-step explanation:

n1 = 1400 ; p1 = 0.50 ; n2 = 1320 ; p2 = 0.38

Confidence interval = mean ± margin of error

Mean = p1 - p2

Point estimate :

p1 - p2 = 0.50 - 0.38 = 0.18

Margin of Error (MOE) = Zcritical * S. E

Standard Error(S. E) :

Sqrt[(p1(1-p1)/n1) + (p2(1-p2)/n2)]

(p1(1-p1)/n1) = 0.50(0.50) / 1400 = 0.0001785

(p2(1-p2)/n2) = 0.38(0.62) / 1320 = 0.0001784

S. E = sqrt(0.0001785 + 0.0001784)

S. E = sqrt(0.0003569)

S. E = 0.0188917

Zcritical at 98% = 2.326

MOE = Zcritical * S. E

MOE = 2.326 * 0.0188917

MOE = 0.0439420942

MOE = 0.0439

Confidence interval = mean ± margin of error

Confidence interval = 0.18 ± 0.0439

Lower boundary = (0.18 - 0.0439) = 0.1361

Upper boundary = (0.18 + 0.0439) = 0.2239

(0.1361 ; 0.2239)


Related Questions

a company that sells annuities must base the annual payout on the probability distribution of the length of life of the participants in the plan. suppose the probability distribution of the lifetimes of the participants in the plan is approximately normal with mean equal to 66.3 years and standard deviation equal to 3.6 years. nine participants are randomly selected. what is the probability that the average age at death of these nine participants will exceed 68 years

Answers

Answer:

0.0778 = 7.78% probability that the average age at death of these nine participants will exceed 68 years

Step-by-step explanation:

To solve this question, we need to understand the normal probability distribution and the central limit theorem.

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 zscore 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 pvalue, we get the probability that the value of the measure is greater than X.

Central Limit Theorem

The Central Limit Theorem estabilishes 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.

Approximately normal with mean equal to 66.3 years and standard deviation equal to 3.6 years.

This means that [tex]\mu = 66.3, \sigma = 3.6[/tex]

Sample of 9:

This means that [tex]n = 9, s = \frac{3.6}{\sqrt{9}} = 1.2[/tex]

What is the probability that the average age at death of these nine participants will exceed 68 years?

This is 1 subtracted by the pvalue of Z when X = 68. So

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

By the Central Limit Theorem

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

[tex]Z = \frac{68 - 66.3}{1.2}[/tex]

[tex]Z = 1.42[/tex]

[tex]Z = 1.42[/tex] has a pvalue of 0.9222

1 - 0.9222 = 0.0778

0.0778 = 7.78% probability that the average age at death of these nine participants will exceed 68 years

Olivia has 2 gallons and 3 quarts of vanilla ice cream and 1 gallon and 2 quarts of chocolate ice cream left over from a party What is the total number of gallons and quarts of ice cream that Olivia has left over?​

Answers

Answer:

4 gallons 1 quart total ice cream

first you add the gallons and the quarts.

so, 2 gallons vanilla + 1 gallon chocolate is 3 gallons.

3 quarts vanilla + 2 quarts chocolate is 5 quarts.

4 of the 5 quarts are taken to make up another gallon.

so the answer is 4 gallons 1 quart total ice cream.

Silas brought an ice chest to the picnic. A model of the ice chest is shown below . 15in Width, 30 inches length, and 15 inches height. What is the volume, in cubic inches of the ice chest?​

Answers

Answer:

6,750 in.³

Step-by-step explanation:

The ice chest is a rectangular prism or a cuboid.

Volume of the ice chest = volume of rectangular prism = l*w*h

Where,

l = 30 in.

w = 15 in.

h = 15 in.

Volume = 30*15*15 = 6,750 in.³

if f(x) =2((x)), find f(-1/4)​

Answers

Answer:

Combine

f and  1/4.

and u get - f/4

Step-by-step explanation:

Answer:

-1/2

Step-by-step explanation:

2(-1/4)

Pls helppp I don’t understand also if you can can you show the works pls if you can tho

Answers

Answer:

I would help but it is just black try to repost it and i will tell you what it is

Step-by-step explanation:

Answer There is only a black picture :)

Graph the inequality on a grid which resembles the image. 400x + 4y < 2000

Answers

Answer:

te awnser is

Step-by-step explanation:

For every quarter spent, Reggie receives 75 food pebbles to feed the fish at a hatchery. Reggie has thrown 600 food pebbles into the fish pools. How many quarters did Reggie spend at the hatchery?

Answers

Rigger has spent eight quarters

Answer:

8

Step-by-step explanation:

What is the value of p in the equation
8p +2 = 4p - 102
1) 1
2) -1
3) 3
4) -3

Answers

Answer:

-26

Step-by-step explanation:

sorry but from my calculations I didn't get any of the options I got -26

Help me out thanks !!!!!

Answers

Answer:

B) ∠SBY = 117°

Step-by-step explanation:

interior angles in a pentagon = (5x180) - 360 = 540°

each angle = 540/5 = 108°

interior angles in a octagon = (8x180) - 360 = 1080°

each angle = 1080/8 = 135°

∠SBY = 360 - 108 - 135 = 117°

Point KK is located at (5,-4)(5,−4) on the coordinate plane. Point KK is reflected over the xx-axis to create point K'K

What ordered pair describes the location of K'?K

Answers

Answer:

The ordered pair that describes the location of K' is (5,4).

Step-by-step explanation:

Reflection over the x-axis:

When a point is reflected over the x-axis, it's x-coordinate stays the same, while the signal of the y-coordinate is changed. So

(x,y) -> (x,-y)

In this question:

Point K(5,-4)

Reflection over the x-axis:

(5,-4) -> (5,-(-4)) -> (5,4)

The ordered pair that describes the location of K' is (5,4).

(fractions) 3/4 + 1/5

Answers

Answer:

19/20

Step-by-step explanation:

write all numerators above the least common denominator 20

15+4/20

add the numbers

19/20

Answer: 19/20

Step-by-step explanation:

Find your common denominator

3/4

Multiply by 5

15/20

1/5

Multiply by 4

4/20 + 15/20= 19/20

Hope this helped :)

find the area of the triangle

Answers

Answer:

Step-by-step explanation:

You know two sides and the angle between them. Use the Law of Cosines to find the third side.

q = √(p²+r²-2pr·cosQ) ≅ 8.533 units

Use Heron's formula to find area

semi-perimeter s = (p+q+r)/2 ≅ 10.317 units

area = √(s(s-p)(s-q)(s-r)) ≅ 16.3 units²

Help on question 5 please :))

Answers

Answer:

the answer is I LIKE YOUR CUT G

Step-by-step explanation:

your a bot at fortnite

Answer:

b. Substitute 8x+4 for y in the first equation.

-7( 2y - 3x + 9 ) =
Plz help

Answers

Answer:

21x - 14y - 63

Step-by-step explanation:

Rearrange the terms so it's: -7(-3x + 2y + 9)

Then distribute it and you have your answer, unless you know what x and y are

what is 9^7 written in expanded form ​

Answers

Answer:

9*9*9*9*9*9*9

Step-by-step explanation:

it's basically 9 multiply by itself for 7 times

Please find the circumference, will give brainliest!

Answers

Answer:

43.96

Step-by-step explanation:

Hi. I need help with math. 8th grade.

Answers

Answer:

260 is the answer. jjrjejjehene

Based on the scatterplot below what is the most likely value for pounds of apples phone number of Apples is 60

Answers

this is a PICTURE

i HOPE IT'S HELP

You and three friends order a large pizza and three sodas at Blue Mountain Pizza.
- The sub total is 32.85.
- There is a 7% sales tax
- You want to leave an 18% tip on the price of the meal plus tax.

If the bill is divided evenly how much will each person pay? (Round to the nearest cent)
Please show work!

Answers

Answer:

$13.20

Step-by-step explanation:

7% = 0.7 so you add that to $32.85 = $33.55

18% of $33.55 is 6.039 so you add that to $33.55 = 39.589

That is the total of the bill so you divide it by 3

39.589 /3 =13.1963

rounded to the nearest cent is $13.20

can someone help me please

Answers

Answer:

i think its b

Step-by-step explanation:

How to get 10 with the numbers 7, 11, 4 and 2 in that order?

Answers

Answer:

Huh!! What is this question supposed to mean?

write
[tex] \frac{12}{25?} [/tex]
as a decimal and as a percent​

Answers

It’s .48 hope this helps you
25x4=100
12x4=48
48/100, 48%, 0.48

A flagpole is 4 meters tall. How many
centimeters tall is the flagpole?

Answers

Answer:

400 cm

Step-by-step explanation:

100 centimeters in a meter.

4 * 100 = 400

help me with this thank you​

Answers

Answer: think it’s c 4/28

Step-by-step explanation:

Answer:

B

Step-by-step explanation:

A group of 20 students attempting a MathematicalChallenge have an average age of 11. When their teacher is included their average age is12. What is the age of the teacher?

Answers

Answer:

32.

1st get the total age of the students

x/20 = 11

x=11x20

x =220 (total age of students)

add y ( teachers age) to the equation

(220 + y)/21=12

y= 32

Answer:

32

Step-by-step explanation:

20 * 11= 220

21 * 12= 252

252-220=32

2/5 x 30 pls help me

Answers

Answer:

12

Step-by-step explanation:

Answer:

The answer is 12.

PLEASE HELP I WILL GIVE BRAINLIEST IF YOU GET IT RIGHT 7TH GRADE MATHH

Answers

Answer:

990

Step-by-step explanation:

(21*18*2)+(21*3*2)+(18*3*2)

=990

yo momma is 600 pounds she eats 300 more pounds of food and gets fatter how many more pounds does she need to get to weigh 3000 pounds

Answers

Answer:

2100

Step-by-step explanation:

L M A O

A rectangular balcony is 10 feet long and 4 feet wide. What is its area?

Answers

10 x 4 = 40cm^3

The area is 40cm^3

The same survey database cited in exercise 4.3.1 (A-5) shows that 32 percent of U.S. adults indicated that they have been tested for HIV at some point in their life. Consider a simple random sample of 15 adults selected at a time. Let X be the number of adults who have been tested for HIV in the sample. For the following, find the numerical answer and describe the answer in words:

a. Three
b. Between five and nine, inclusive
c. More than five, but less than 10
d. Six or more
e. Less than five
f. Find the mean and the variance of the number of people tested for HIV in samples of size 15.

Answers

Answer:

a. P(X = 3) = 0.145736

b. P(5≤X≤9) = 0.5462

c. P(5<X<10) = 0.3332

d. P(X≥6) = 0.3393

e. P(X<5) = 0.4477

f. Mean = 4.8, Variance = 3.264

Step-by-step explanation:

Given - The same survey database cited in exercise 4.3.1 (A-5) shows

             that 32 percent of U.S. adults indicated that they have been

             tested for HIV at some point in their life. Consider a simple

             random sample of 15 adults selected at a time. Let X be the

             number of adults who have been tested for HIV in the sample.

To find - For the following, find the numerical answer and describe

              the answer in words:

              a. Three

              b. Between five and nine, inclusive

              c. More than five, but less than 10

              d. Six or more

              e. Less than five

              f. Find the mean and the variance of the number of people

                 tested for HIV in samples of size 15.

Proof -

Given that , n = 15, p = 32% = 0.32

Now,

a.

P(X = 3) = binomial distribution (3, 15, 0.32, 0)

             = [tex]\left(\begin{array}{ccc}15\\3\end{array}\right)(0.32)^{3}(1-0.32)^{15 - 3}[/tex]

             = 455(0.032768)(0.009774)

             = 0.145736

⇒P(X = 3) = 0.145736

b.

P(5≤X≤9) = P(X = 5) + P(X = 6) + P(X = 7) + P(X = 8) + P(X = 9)

               = [tex]\left(\begin{array}{ccc}15\\5\end{array}\right)(0.32)^{5}(1-0.32)^{15 - 5}[/tex]+ [tex]\left(\begin{array}{ccc}15\\6\end{array}\right)(0.32)^{6}(1-0.32)^{15 - 6}[/tex] + [tex]\left(\begin{array}{ccc}15\\7\end{array}\right)(0.32)^{7}(1-0.32)^{15 - 7}[/tex] + [tex]\left(\begin{array}{ccc}15\\8\end{array}\right)(0.32)^{8}(1-0.32)^{15 - 8}[/tex]+ [tex]\left(\begin{array}{ccc}15\\9\end{array}\right)(0.32)^{9}(1-0.32)^{15 - 9}[/tex]

               = 0.213 + 0.1671 + 0.1011 + 0.0476 + 0.0174

               = 0.5462

⇒P(5≤X≤9) = 0.5462

c.

P(5<X<10) = + P(X = 6) + P(X = 7) + P(X = 8) + P(X = 9)

                 =  [tex]\left(\begin{array}{ccc}15\\6\end{array}\right)(0.32)^{6}(1-0.32)^{15 - 6}[/tex] + [tex]\left(\begin{array}{ccc}15\\7\end{array}\right)(0.32)^{7}(1-0.32)^{15 - 7}[/tex] + [tex]\left(\begin{array}{ccc}15\\8\end{array}\right)(0.32)^{8}(1-0.32)^{15 - 8}[/tex]+ [tex]\left(\begin{array}{ccc}15\\9\end{array}\right)(0.32)^{9}(1-0.32)^{15 - 9}[/tex]

               =  0.1671 + 0.1011 + 0.0476 + 0.0174

               = 0.3332

⇒P(5<X<10) = 0.3332

d.

P(X≥6) = 1 - P(X < 6)

           = 1 - P(X ≤ 5)

           = 1 - binomial(5, 15, 0.32, 1)

           = 1 - 0.6607

           = 0.3393

⇒P(X≥6) = 0.3393

e.

P(X<5) = P(X≤4)

           = binomial (4, 15, 0.32, 1)

           = 0.4477

⇒P(X<5) = 0.4477

f.

Mean = np

         = 15(0.32)

         = 4.8

⇒Mean = 4.8

Variance = np(1-p)

              = 15(0.32)(1 - 0.32)

              = 4.8(0.68)

              = 3.264

⇒Variance = 3.264

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