The survey included a random sample of 640 western residents and 540 northeastern residents. 39% of the western residents and 51% of the northeastern residents reported that they were completely satisfied with their local telephone service. Find the 99% confidence interval for the difference in two proportions

Answers

Answer 1

Answer:

The 99% confidence interval for the difference in two proportions is (0.0456, 0.1944).

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.

Western residents:

39% out of 640, so:

[tex]p_1 = 0.39[/tex]

[tex]s_1 = \sqrt{\frac{0.39*0.61}{640}} = 0.0193[/tex]

Eastern residents:

51% out of 540, so:

[tex]p_2 = 0.51[/tex]

[tex]s_2 = \sqrt{\frac{0.51*0.49}{540}} = 0.0215[/tex]

Distribution of the difference:

[tex]p = p_2 - p_1 = 0.51 - 0.39 = 0.12[/tex]

[tex]s = \sqrt{s_2^2+s_1^2} = \sqrt{0.0215^2+0.0193^2} = 0.0289[/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].

99% confidence level

So [tex]\alpha = 0.01[/tex], z is the value of Z that has a p-value of [tex]1 - \frac{0.01}{2} = 0.995[/tex], so [tex]Z = 2.575[/tex].

The lower bound of the interval is:

[tex]p - zs = 0.12 - 2.575*0.0289 = 0.0456[/tex]

The upper bound of the interval is:

[tex]p + zs = 0.12 + 2.575*0.0289 = 0.1944[/tex]

The 99% confidence interval for the difference in two proportions is (0.0456, 0.1944).


Related Questions

Destiny just received two separate gifts from her great-great-grandmother.
The first gift is a box of 18 chocolate candy bars, and the second gift is a pack of 12 cookies.
Destiny wants to use all of the chocolate candy bars and cookies to make identical snack bags for her cousins.
What is the greatest number of snack bags that Destiny can make?

Answers

Answer:

Destiny will be able to create 12 identical snack bags.

Step-by-step explanation:

Given that a snack bag will be 1 chocolate candy bar, and 1 cookie, we have to subtract 1 chocolate for every cookie she has, and that will leave us with 6 chocolate bars left. The equation for this is 18 - 12 = 6.

What is the distance from point Yto wx in the figure below?
W 16 Z
30
X
1612
34
O A. 4
O B. 162
O C. 16
O D. Cannot be determined
E. 16/3
F. 8

Answers

The length of YZ in the similar triangle given is calculated using Pythagoras theorem which gave us 16√3

What are Similar Triangle

Similar triangles are two or more triangles that have the same shape but may be different sizes. They have the same angles and corresponding sides that are proportional.

In this problem, we need to use the concept of ratio and proportions to find the length of YZ

However, we can simply use Pythagoras theorem to determine the length.

According to Pythagoras' Theorem, the square of the hypotenuse, or side opposite the right angle, in a right-angled triangle, is equal to the sum of the squares of the other two sides.

It is expressed as the equation a² + b² = c².

This is because the triangles forms a right angled triangle and we can easily apply that here.

YZ² = 16² + (16√2)²

YZ² = 768

YZ = √768

YZ = 16√3

The length or distance from point Y to WX which is the same as the length of YZ is calculated as 16√3.

Learn more on similar triangle here;

https://brainly.com/question/14285697

#SPJ1

Answer:

C. 16

Step-by-step explanation:

I hope this helps :)

Algebra two divide plz help​

Answers

Answer:

-  x³ - 2x² + 3 - 1 / x

Step-by-step explanation:

(4x³ - 8x² + 12x - 4) / (-4x)

-  x³ - 2x² + 3 - 1 / x

Suppose a young sedentary woman wanted to lose 30 pounds of body fat in a period of 20 weeks. She now weighs 160 pounds and her activity level is such so she needs 15 Calories per pound of body weight to maintain her weight. Calculate the number of Calories she may consume daily in order to lose the 30 pounds by diet only. 1,000 1,250 1,400 1,650 1,900

Answers

Answer:

The answer is "1900"

Step-by-step explanation:

It takes 500 fewer calories per day for her to lose 1 lb of weight every week.

[tex]\to (15 \times 160)-500 =(2400)-500 =2400-500=1900[/tex]

Sarah has two similar rectangular boxes. The dimensions of Box 1 are four times those of Box 2.

How many times greater is the surface area of Box 1 than the surface area of Box 2?

8

64

4

16

Answers

Answer:

16

Step-by-step explanation:

an area is always calculated by multiplying 2 dimensions.

when changing the dimensions, then the change factors for EACH dimension go into the calculation too.

therefore, when both dimensions of an area are enlarged 4 times, then the area is enlarged 4×4 = 16 times.

this just propagates to the whole surface area of an object, as each individual area of the overall surface area is enlarged by the same factor. and so, the sum of all the individual areas (= altogether the surface area of the object) is also enlarged in total by the same factor.

just think

16×a + 16×b + 16×c ... = 16×(a+b+c+...)

and you understand why.

What is the domain of the function Y = In
-X+3
2
0x62
O x32
O X<3
O
X> 3
ASAP

Answers

Answer:

i think 1/58 is correct

i hope its help you

can someone help me pls

Answers

Answer:

D NO IS THE WRITE ANSWER .

Answer:

D)

Step-by-step explanation:

Students at a virtual school are allowed to sign up for one math class each year. The numbers of students signing up for various math classes for the next school
year are given in the following table:
Grade Geometry Algebra II Pre-Calculus AP Statistics Total
10th
150
75
25
5
255
11th
50
100
75
20
245
12th
10
50
100
65
225
Total 210
225
200
90
725
Part A: What is the probability that a student will take AP Statistics? (2 points)
Part B: What is the probability that a 12th-grader will take either Pre-Calculus or AP Statistics? (2 points)
Part C: What is the probability that a student will take Algebra II given that he or she is in the 11th grade? (2 points)
Part D: Consider the events "A student takes Algebra II and "A student is a 10th-grader. Are these events independent? Justify your answer. (4 points)

Answers

A well formatted table of the distribution is attached below :

Answer:

0.124

0.733

0.408

Step-by-step explanation:

Using the table Given :

1.) P(AP Statistics) = 90 / 725 = 0.124

2.) P(12th grade ; Precalculus or AP Statistics) = (100 + 65) / 225 = 165 /225 = 0.733

3.) P(Algebra 11 | 11th grade) = P(Algebara11 n 11th grade) / P(11th grade) = 100 / 245 = 0.408

In the Data Analysis portion of the article the authors report that they completed a power analysis to determine the power of their study with the sample size utilized. They report a power of 90%. What does this mean

Answers

Answer:

Kindly check explanation

Step-by-step explanation:

The power of a test simply gives the probability of Rejecting the Null hypothesis, H0 in a statistical analysis given that the the alternative hypothesis, H1 for the study is true. Hence, the power of a test can be referred to as the probability of a true positive outcome in an experiment.

Using this definition, a power of 90% simply means that ; there is a 90% probability that the a Pvalue less Than the α - value of an experiment is obtained if there is truly a significant difference. Hence, a 90% chance of Rejecting the Null hypothesis if truly the alternative hypothesis is true.

SI unit of areaWhat is the SI unit of area ​

Answers

square meter is the SI unit of area.

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forty-five percent of the students in a dorm are business majors and fifty-five percent are non-business majors. business majors are twice as likely to do their studying at the library as non-business majors are. half of the business majors study at the library. if a randomly slected student from the dorm studies at the library, what is the probability the student is a business major

Answers

Solution :

Defining the following events as :

B : Being a Business major

α : Studying at the library

∴ Given that :

[tex]$P(B) = \frac{45}{100}$[/tex]

         = 0.45

Again, P [ Studying at the library | Being a Business major ] = 2 P [ Studying at the library | Being a non business major ]

[tex]$P[ \alpha | B] = 2 P[\alpha | B^C]$[/tex]   .......(1)

Again,

[tex]$P[\text{Studying at the library } | \text{ Being a business major}] = \frac{1}{2} = 0.50$[/tex]

[tex]$P(\alpha | B) = 0.50$[/tex]

From (1), we get

[tex]$P(\alpha | B^C) = \frac{1}{2} . P(\alpha | B)$[/tex]

              [tex]$=\frac{1}{2} \times 0.50$[/tex]

              = 0.25

Therefore, we need,

= P[  The students is a Business major | The student studies at the library ]

[tex]$=P(B | \alpha)$[/tex]

By Bayes theorem

[tex]$=\frac{P(B). P(\alpha | B)}{P(B).P(\alpha | B) + P(B^C). P(\alpha | B^C)}$[/tex]

[tex]$=\frac{0.45 \times 0.50}{0.45 \times 0.50 + 0.55 \times 0.25}$[/tex]

= 0.6207

A group consists of 5 men and 8 women. 4 people are selected to attend a conference.
a. In how many ways can 4 people be selected from this group of ​13?
b. In how many ways can 4 women be selected from the 8 ​women?
c. Find the probability that the selected group will consist of all women.

a. The number of ways to select 4 people from the group of 13 is ___.

b. The number of ways to select 4 women from the group of 8 women is ___.

c. The probability is ___.
​(Type an integer or a simplified​ fraction.)

Answers

Answer:

in four (4) ways 4 people can be selected

GUYS I NEED HELP PLEASE!!!

Answers

Answer:

A.

Step-by-step explanation:

π/4 radians = 45°

In a 45-45-90 degree angle, the ratio of the lengths of the sides is

1 : 1 : √2

x = y = 1/√2

x = y = √2/2

Answer: A.

Answer:

A

Step-by-step explanation:

π/4 rad is 45°

cos 45° and sin 45° are both equal to (√2 / 2)

If you're curious, cos delta = x-coordinate while sin delta = y-coordinate

According to Fidelity Investment Vision Magazine, the average weekly allowance of children varies directly as their grade level. In a recent year, the average allowance of a 9th-grade student was 9.66 dollars per week. What was the average weekly allowance of a 5 th-grade student?​

Answers

The average weekly allowance of a 5th grade student as calculated using direct variation with the information provided by Fidelity Investment Vision Magazine is 5.367 dollars per week.

The question given is a direct variation problem:

Let:

Average weekly allowance = [tex]a[/tex]

• Grade level = [tex]g[/tex]

If Average weekly allowance varies directly as grade level , then , then the direct variation between the variables can be expressed as :

[tex]a = k * g[/tex]

Where ,  [tex]k[/tex] = constant of proportionality

We can obtain the value of k from the given values of a and g

[tex]9.66 = k * 9\\9.66 = 9k\\k = 9.66/9[/tex]

Our equation becomes:

[tex]a = (9.66/9) * g[/tex]

[tex]a = (9.66/9) * 5\\a = 5.367[/tex] (rounded to 3 decimal places)

Hence, using proportional relationship, the average weekly allowance for a 5th grade student is [tex]5.367[/tex] per week

Learn more about direct variation here:

https://brainly.com/question/17257139

A one lane highway runs through a tunnel in the shape of one half a sine curve cycle

Answers

The sine curve equation, y = 10·sin(x·π/24), that models the entrance of the

tunnel with a cross section that is the shape of half of a sine curve and the

height of the tunnel at the edge of the road, (approximately 7.07 ft.) are

found by applying the following steps

(a) The equation for the sine curve is y = 10·sin(x·π/24)

(b) The height of the tunnel at the edge of the road is approximately 7.07 feet

The reason for the above answers are presented as follows;

(a) From a similar question posted online, the missing part of the question

is, what is the height of the tunnel at the edge of the road

The known parameters;

The shape of the tunnel = One-half sine curve cycle

The height of the road at its highest point = 10 ft.

The opening of the tunnel at road level = 24 ft.

The unknown parameter;

The equation of the sine curve that fits the opening

Method;

Model the sine curve equation of the tunnel using the general equation of a sine curve;

The general equation of a sine curve is y = A·sin(B·(x - C) + D

Where;

y = The height at point x

A = The amplitude = The distance from the centerline of the sine wave to the top of a crest

Therefore;

The amplitude, A = The height of half the sine wave = The height of the tunnel = 10 ft.

D = 0, C = 0 (The origin, (0, 0) is on the left end, which is the central line)

The period is the distance between successive points where the curve passes through the center line while rising to a crest

Therefore

The period, T = 2·π/B = 2 × Opening at the road level = 2 × 24 ft. = 48 ft.

T = 48 ft.

We get;

48 = 2·π/B

B = 2·π/48 = π/24

By plugging in the values for A, B, C, and D, we get;

y = 10·sin((π/24)·(x - 0) + 0 = 10·sin(x·π/24)

The equation of the sine curve that fits the opening is y = 10·sin(x·π/24)

(b) The height of the tunnel at the edge of the road is given by substituting

the value of x at the edge of the road into the equation for the sine curve

as  follows;

The width of the shoulders = 6 feet

∴ At the edge of the road, x = 0 + 6ft = 6 ft., and 6 ft. + 12 ft. = 18 ft.

Therefore, we get;

y = 10 × sin(6·π/24) = 10 × sin(π/4) = 5×√2

y = 10 × sin(18·π/24) = 10 × sin(3·π/4) = 5×√2

The height of the, y, tunnel at the edge of the road where, x = 6, and 18 is y = 5·√2 feet ≈ 7.07 ft.

Learn more about the sine curve here;

https://brainly.com/question/3827606

What are the coordinates of point K?
A (-2,4)
B (-2,-4)
C (2,-4)
D (2, 4)

Answers

Answer:

A

Step-by-step explanation:

I guess that is the answer

If p-1/p=4,find the value of P2+1/p2​

Answers

Answer:

18

Step-by-step explanation:

(p-1/p)² = 4²

p² + 1/p² - 2(p)(1/p) = 16

p²+1/p² -2 =16

so, p²+1/p² = 16+2

= 18

n rectangle ABCD, point E lies half way between sides AB and CD and halfway between sides AD and BC. If AB=3 and BC=11, what is the area of the shaded region? Write your answer as a decimal, if necessary. Do not include units in your answer.

Answers

*see attachment for clearer diagram

Answer:

16.5

Step-by-step explanation:

BC = 11

AB = 3

Area of the shaded region = area of ∆AEB + area of ∆CED

Area of a triangle is given as,

A = ½*base*height

Find the area of each triangle and add together

✔️Area of ∆AEB = ½*bh

Where,

base (b) = 3

height (h) = ½(BC) = ½(11) = 5.5

Area of ∆AEB = ½*3*5.5 = 8.25

✔️Area of ∆CED = ½*bh

Where,

b = 3

h = ½(BC) = ½(11) = 5.5

Area of ∆CED = ½*3*5.5 = 8.25

✅Area of the shaded region = area of ∆AEB + area of ∆CED

= 8.25 + 8.25

= 16.5

What must be true about the discriminant of this quadratic equation for the mentioned values of k? Assume p>0.

value of the discriminant k > 0
Options:
B^2 - 4ac= 0
B^2 - 4ac is greater than 0
B^2 - 4ac is less than 0

Answers

Answer:

Step-by-step explanation:b

No real roots. Roots will have imaginary numbers. This means the quadratic is either always above the axis, or always below.

One real root. The graph touches the  x -axis in one place.  →

Two real roots. The graph crosses the x -axis twice.

if x=2 and y=3. What is x*y/xy+x*y​

Answers

Answer

its uhhhhh i dont know

Step-by-step explanation:

a motercycle can travel 60 miles per gallon. approximently how many gallons of fuel will the motercycle need to travel 40 km
[1 mile = 1.6km]

Answers

Answer:

Step-by-step ex0.72

A magazine conducted a survey among its readers in a certain state. They reported the following results:
Out of 1200 respondents, 312 are professionals, 470 are married, 524 are college graduates, 193 are professional college graduates, 178 are married college graduates, 136 are married professionals, and 35 are married professional college graduates.
What is the probability that a randomly selected reader in that state is:

a. Either married, or a college graduate, or a professional?
b. Neither married, nor a college graduate, nor a professional?

Answers

Answer:

The answer is "0.695 and 0.305".

Step-by-step explanation:

Please find the attached file of the given question:

From question a:

[tex]\text{P(Either married, or a college graduate, or a professional)} \\\\=\frac{(312+143+188+191)}{1200}\\ \\ =\frac{834}{1200}\\\\=0.695[/tex]

 From question b:

[tex]\text{P( Neither married, nor a college graduate, nor a professional )}\\\\=\frac{366}{1200} \\\\=0.305[/tex]

help me out, so I can confirm my answers...:)​

Answers

Answer:

Step-by-step explanation:

i) 18 - 2b = 5a

18 - 2b - 5a = 0

-2b -5a = -18

2b + 5a = 18

5a + 2b = 18

ii) 3a = 5b + 17

3a - 5b = 17

At this time x = 3, y = -5, c= 17

ax + by = c is equivelant to 3a -5b = 17

So another equation is:

3a - 5b = 17

Answer from Gauthmath

Step-by-step explanation:

18-2b=5a

we want to make 5a the subject so first we 5a to the left so our new equation is 5a+18-2b=0

then we move the 2b infront of the +18 so then our new equation is 5a+2b+18=0 then. we move the +18 to the other side to give 5a+2b=18

write the first 10 multiplies of 6 and 8 pairs of numbers and find this LCM​

Answers

↪[tex] \huge\rm{answer: } \: \boxed{ \purple{24 }}[/tex]

➖➖➖➖➖➖➖➖➖➖➖➖➖➖➖

M(6)= {0, 6, 12, 18, 24, 30, 36, 42, 48, 54, 60 ...}

M(8) = {0, 8, 16, 24, 32, 40, 48, 56, 64, 72, 80...}

➖➖➖➖➖➖➖➖➖➖➖➖➖➖➖

I hope you understood!✏

➖➖➖➖➖➖➖➖➖➖➖➖➖➖➖

[tex] \huge\boxed{ \boxed{ \rm{Hope \: this \: helps }}}[/tex]

Answer:

6=0,6,12,18,24,30,36,42,48,54,60

8=0,8,16,24,32,40,48,56,64,72,80

HCF=24,48

LCM=0,6,12,18,,30,36,42,48,54,60,8,16,24,32,40,,56,64,72,80

if a/b = 3 and a + b = 2, what is a - b​

Answers

Answer:

1

Step-by-step explanation:

a/b=3------equation 1

a+b=2-----equation 2

from equation 2

b=2-a

substitute b=2-a in equation 1

a/2-a=3

a=3(2-a)

a=6-3a

a+3a=6

a=6/4

a=3/2

substitute a=3/2 in equation 2

3/2+b=2

3+2b=4

2b=1

b=1/2

a-b=3/2-1/2

a-b=(3-1)/2

a-b=2/2

a-b=1


In the equation 11 - 4(x +4) = 6x, the first step is to simplify 11 - 4.
True
False

Answers

Answer:

False

Step-by-step explanation:

You first need to distribute the -4 to (x+4).

Find the mean, median, and mode of the following data. If necessary, round to one more decimal place than the largest number of decimal places given in the data.

MLB Batting Averages
0.2750.275 0.3190.319 0.3140.314 0.2800.280 0.2880.288
0.3140.314 0.2950.295 0.2960.296 0.3170.317 0.2760.276
0.2740.274 0.2890.289 0.2950.295 0.2760.276 0.2750.275
0.2960.296 0.3110.311 0.2890.289 0.2830.283 0.3120.312

Answers

Answer:

0.2937 ;

0.292 ;

0.275, 0.314, 0.295, 0.296, 0.276, 0.289

Step-by-step explanation:

0.275 0.319 0.314 0.280 0.288 0.314 0.295 0.296 0.317 0.276 0.274 0.289 0.295 0.276 0.275 0.296 0.311 0.289 0.283 0.312

Reordered data :

0.274, 0.275, 0.275, 0.276, 0.276, 0.280, 0.283, 0.288, 0.289, 0.289, 0.295, 0.295, 0.296, 0.296, 0.311, 0.312, 0.314, 0.314, 0.317, 0.319

The mean : ΣX / n ; n = sample size, = 20

Mean = 5.874 / 20 = 0.2937

The median : 1/2(n+1)th term

Median = 1/2(21)th term = 10.5 th term

Median = (10th + 11th) terms / 2

Median = (0.289+0.295) / 2 = 0.292

The mode = 0.275, 0.314, 0.295, 0.296, 0.276, 0.289 (values with ten highest number of occurence.)

Find the measure of x. X=8, x=7, x=9, x=11

Answers

Answer:

[tex]\frac{135}{15} =\frac{15(x+2)}{15}[/tex]

[tex]9=x+2[/tex]

[tex]x=7[/tex]

OAmalOHopeO

A cyclist rides his bike at a speed of 15 miles per hour. What is this speed in kilometers per hour? How many kilometers will the cyclist travel in 4 hours? In your computations, assume that 1 mile is equal to 1.6 kilometers. Do not round your answers.

Answers

Answer:

Step-by-step explanation:

Speed = (15 mi)/hr × (1.6 km)/mi = (24 km)/hr

:::::

(4 hr) × (24 km)/hr = 96 km

1. Choose the correct decimal for "three tenths."
3
0.03
0.003
0.3
Please hurry, if you do reply thank u, it means alot! <3 :)

Answers

Answer:

3 tenths means 3 over ten represented as as 3/10 and 10 has one zero I.e tenth different from hundredths which has 2 zeros so our decimal shld also have one zero which is 0.3...so 0.3 is the answe hope it helps❤

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