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
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).
d) A movie time was 2hours. 10% of the time was taken advertisement. How long was the actual movie?
Answer:
108 minutes
Step-by-step explanation:
Lets say that M+A is the time of the movie and the advertisement, so;
M+A = 2
And we know that 10% of that time is advertisement, mathematically that is:
A = 0,1*2
So replacing the second equation in the first one we have;
M + 0,1*2 = 2
M = 2-0,1*2 = 1,8 hours
We can convert hours into minutes multiplying by 60
1,8h*60min/h = 108min
Economists predict that Americans will spend $1,180 on electonics in
2020. this is a 6.8% increase from last year. What did Americans spend
last year?
5x^2-4x=6
Solve for X.
Answer:
x= (2+ √ 34) /5 , (2- √ 34) /5
decimal form= 1.566
Step-by-step explanation:
The area of a circle is 144cm².Find the radius
Answer:
It's a decimal, so it's around 6.771cm
Step-by-step explanation:
First, divide 144cm² by pi, or 3.14. Then find the square root of the answer, giving you the radius. The formula for the area of a circle is pi x radius squared, so to find out the radius you just use this formula in reverse.
If I messed up or didn't make my explanation clear, please comment.
Answer:
radius is [tex]\frac{12}{\sqrt{\pi } }[/tex] = 6.77 cm
Step-by-step explanation:
we know,
[tex]\pi[/tex] × r² = Area
⇒ [tex]\pi[/tex] × r² = 144
⇒ r² =[tex]\frac{144}{\pi}[/tex]
⇒ r= [tex]\frac{12}{\sqrt{\pi } }[/tex]
∴ r= [tex]\frac{12}{\sqrt{\pi } }[/tex]
pls mark this as the braniliest
The graph shows the distribution of the number of text messages young adults send per day. The distribution is approximately Normal, with a mean of 128 messages and a standard deviation of 30 messages.
What percentage of young adults send more than 158 text messages per day?
16%
34%
68%
84%
Answer:
You'd think its 34% but apparently it's 16%.
I hope this is right. If its not then it must be 34%.
(A) -- or maybe (B). 80% confident it is A.
ED2021
Cual es el capital que prestado al 10% bimestral durante 6 meses y 10 días produce un interés de 1140
Answer:
El capital que prestado al 10% bimestral durante 6 meses y 10 días produce un interés de $1140 es $3,600.
Step-by-step explanation:
Para determinar cuál es el capital que prestado al 10% bimestral durante 6 meses y 10 días produce un interés de $1140 se debe realizar el siguiente cálculo:
6 / 2 = 3
10/60 = 0.16666
10 x 3.1666 = 31.666
31.666 = 1140
100 = x
100 x 1140 / 31.666 = X
114,000 / 31.666 = X
3,600 = X
Por lo tanto, el capital que prestado al 10% bimestral durante 6 meses y 10 días produce un interés de $1140 es $3,600.
In the diagram below, the circle has a radius of 25 inches. The area of the shaded sector is 125π in^2. Determine and state the measure of angle Q of the shaded sector. Show all your work that leads to the final answer. Please take a CLEAR picture of your work and upload here. Thank you.
Answer:
72 degrees
Step-by-step explanation:
Area of a sector=(pi*r^2)*(Theta/360)
125*pi=pi*(625)*(theta/360)
(125*360)/625=theta
Theta=72 degrees
The angle theta of the sector of the given circle is 72 degrees.
We have given that,
In the diagram below, the circle has a radius of 25 inches.
The area of the shaded sector is 125π in^2.
What is the formula area of the sector?[tex]Area \ of \ a \ sector=(pi*r^2)*(\Theta/360)[/tex]
Therefore we get,
[tex]125*pi=pi*(625)*(\theta/360)[/tex]
[tex](125*360)/625=\theta[/tex]
[tex]\theta=72 degrees[/tex]
Therefore we get the angle of the sector of the given circle is 72 degrees.
To learn more about the area of sector visit:
https://brainly.com/question/22972014
#SPJ2
Integers that are not whole numbers
Answer:
a negative integer
Step-by-step explanation:
What's the measure of an arc with a central angle of 120°?
Answer:
the answer is 240 degrees
Trong một lớp học có $35$ sinh viên nói được tiếng Anh, $25$ sinh viên nói được tiếng Nhật trong đó có $10$ sinh viên nói được cả tiếng Anh và tiếng Nhật. Mỗi sinh viên trong lớp nói được ít nhất một trong hai: tiếng Anh hoặc tiếng Nhật. Hỏi sỹ số của lớp là bao nhiêu
Answer:
please write this question in English then I give answer
Please solve the equation 4X-25=71
What’s the distance between (4,-9) and (5,3)
Answer: Distance = √145
Concept:
Here, we need to know the concept of the distance formula.
The distance formula is the formula, which is used to find the distance between any two points.
If you are still confused, please refer to the attachment below for a clear version of the formula.
Solve:
Given information
(x₁, y₁) = (4, -9)
(x₂, y₂) = (5, 3)
Given formula
[tex]Distance = \sqrt{(x_2-x_1)^2+(y_2-y_1)^2}[/tex]
Substitute values into the formula
[tex]Distance = \sqrt{(5-4)^2+(3+9)^2}[/tex]
Simplify values in the parentheses
[tex]Distance = \sqrt{(1)^2+(12)^2}[/tex]
Simplify exponents
[tex]Distance = \sqrt{1+144}[/tex]
Simplify by addition
[tex]Distance = \sqrt{145}[/tex]
Hope this helps!! :)
Please let me know if you have any questions
Answer:
[tex]\boxed {\boxed {\sf \sqrt {145} \ or \ 12.04}}[/tex]
Step-by-step explanation:
The distance between 2 points is calculated using the following formula.
[tex]d= \sqrt {(x_2-x_1)^2+(y_2-y_1)^2)[/tex]
In this formula, (x₁, y₁) and (x₂, y₂) are the coordinates of the two points.
We know the two points are (4, -9) and (5,3). If we match the values of the points and the coordinating variable, we see that:
x₁ = 4y₁= -9 x₂ = 5 y₂ = 3Substitute the values into the formula.
[tex]d= \sqrt { ( 5 -4)^2 + ( 3 --9)^2[/tex]
Solve inside the parentheses.
(5-4)= 1 (3 --9) = (3+9) = 12[tex]d= \sqrt {(1)^2 + (12)^2}[/tex]
Solve the exponents.
(1)² = 1 *1 = 1 (12)² = 12 * 12 = 144[tex]d= \sqrt{ 1+144}[/tex]
Add.
[tex]d= \sqrt{145[/tex]
Take the square root.
[tex]d=12.04159458[/tex]
Let's round to the nearest hundredth. The 1 in the thousandth place tells us to leave the 4 in the hundredth place.
[tex]d \approx 12.04[/tex]
The distance between the 2 points is √145 or approximately 12.04.
Select the expression that represents the following statement: 3 times one fourth the difference of 26 and 10.
one fourth x (26 + 10) x 3
one fourth x (26 − 10) x 3
3 x one fourth x 26 − 10
3 x one fourth x 26 x 10
PLEASEE HEPPP
Answer:
the second option #2
one fourth x (26-10) x 3
Step-by-step explanation:
Two of the options (#1 and #4) can be ruled out immediately since they don't involve the difference of 26 and 10.
#3 can be ruled out because the difference needs to be multiplied by one fourth, but this option gives the wrong answer since the multiplication is done before subtraction (BODMAS)
Answer:
c
Step-by-step explanation:
I got it correct on a quiz
Plz someone help me
Step-by-step explanation:
yo
so sorry I can't
really answer it
Find the length of BC, last one
Since this is a right triangle, we can use one of the three main trigonometric functions: sine, cosine, or tangent.
Remember: SOH-CAH-TOA
Looking from the given angle, we know the opposite side and want to know the adjacent side. Therefore, we should use the tangent function.
tan(54) = 16/BC
BC = 16/tan(54)
BC = 11.62 units
Hope this helps!
Urgent please I neeed some help !!!!!!!!!!!!!!!!!!!!!! URGENT 20 point bonus
Answer:
113.1
Step-by-step explanation:
use the formula to solve for volume
Question 3 of 28
What is the length of IN in the right triangle below?
M
19
N
O A. 442
B. 442
O c. 1200
D. 280
Answer:
Option C. √280
Step-by-step explanation:
From the question given above, the following data were obtained
MN = 19
ML = 9
LN =?
We can obtain the value of LN by using the pythagoras theory as illustrated:
M ² = ML² + LN²
19² = 9² + LN²
361 = 81 + LN²
Collect like terms
361 – 81 = LN²
280 = LN²
Take the square root of both side
LN = √280
Therefore, the length of LN is √280
Please Help Me!!! (WORTH 60 POINTS) Will Give Extra points out
Answer:
√11 cm
Step-by-step explanation:
Pythagorean Thereom
a^2 + b^2= c^2
x^2 +5^2=6^2
x^2 + 25 = 36
subtract 25 from both sides
x^2=11
do the square root
x = √11
U looking for BRAINLIEST? I'll give it to the first person to get it right
What is the shape of the distribution shown below?
A: The distribution is skewed to the left.
B: The distribution is approximately symmetrical.
C: The distribution is skewed to the right.
Answer:
A: The distribution is skewed to the left.
Step-by-step explanation:
Skewness:
If the distribution has a long left tail, it is skewed to the left.
If it has a long right tail, it is skewed to the right.
Otherwise, it is approximately symmetrical.
In this question:
Lots of values on the start(left), few on the end(right), so it is skewed to the left, and the correct answer is given by option a.
In the accompanying diagram, ΔA′B′C′ is the image of ΔABC. Which type of transformation is shown in the illustration?
A. rotation
B. translation
C. reflection
D. dilation
Answer:
Reflection
Step-by-step explanation:
It is the opposite of the first,...
Kendall wants to estimate the percentage of vegetarians who are also vegan. She surveys 150 vegetarians and finds that 45 are vegan. Find the margin of error for the confidence interval for the population proportion with a 95% confidence level.
Answer:
0.0733364
Step-by-step explanation:
Given :
Number of vegans = x ;
Sample size, n = 150
Zα/2 ; Zcritical at 95% = 1.96
p = x / n = 45 / 150 = 0.3
Margin of Error :
Zcritical * √(p(1 - p) / n)
1.96 * √(0.3(1 - 0.3) / 150)
Margin of Error :
1.96 * √(0.3 * 0.7) / 150)
1.96 * √0.0014
Margin of Error = 0.0733364
the average temperature at the south pole is -49.62and the average temperature at north pole is -34.68. how much higher is the average temperature at the north pole than at the south pole
Find x so that the points (x,x+1), (x+2,x+3) and (x+3,2x+4) form a right-angled triangle.
Let a, b, and c be vectors each starting at the origin and terminating at the points (x, x + 1), (x + 2, x + 3), and (x + 3, 2x + 4), respectively.
Then the vectors a - b, a - c, and b - c are vectors that point in directions parallel to each of the legs formed by the triangle with these points as its vertices.
If this triangle is to contain a right angle, then exactly one of these pairs of vectors must be orthogonal. In other words, one of the following must be true:
(a - b) • (a - c) = 0
or
(a - b) • (b - c) = 0
or
(a - c) • (b - c) = 0
We have
a - b = (x, x + 1) - (x + 2, x + 3) = (-2, -2)
a - c = (x, x + 1) - (x + 3, 2x + 4) = (-3, -x - 3)
b - c = (x + 2, x + 3) - (x + 3, 2x + 4) = (-1, -x - 1)
Case 1: If (a - b) • (a - c) = 0, then
(-2, -2) • (-3, -x - 3) = (-2)×(-3) + (-2)×(-x - 3) = 2x + 12 = 0 ==> x = -6
which would make a - c = (-3, 3) and b - c = (-1, 5), and their dot product is not zero. Then the triangles vertices are at the points (-6, -5), (-4, -3), and (-3, -8).
Case 2: If (a - b) • (b - c) = 0, then
(-2, -2) • (-1, -x - 1) = (-2)×(-1) + (-2)×(-x - 1) = 2x + 4 = 0 ==> x = -2
which would make a - c = (-3, -1) and b = (-1, 1), and their dot product is also not zero. The vertices are the points (-2, -1), (0, 1), and (1, 0).
Case 3: If (a - c) • (b - c) = 0, then
(-3, -x - 3) • (-1, -x - 1) = (-3)×(-1) + (-x - 3)×(-x - 1) = x ² + 4x + 6 = 0
but the solutions to x here are non-real, so we throw out this case.
So there are two possible values of x that make a right triangle, x = -6 and x = -2.
What are four ways an inequality can be written?
Answer:
There are four ways to represent an inequality: Equation notation, set notation, interval notation, and solution graph.
Find the missing side of the triangle
Answer:
x = 4[tex]\sqrt{2}[/tex]
Step-by-step explanation:
Pytago:
x[tex]x^{2} +7^{2} = 9^{2} \\\\x = \sqrt{9^{2} - 7^{2} } x = 4\sqrt{2}[/tex]
Is the following polynomial or not
5xy^2+3x^2y-2x^2y^2
9514 1404 393
Answer:
is a polynomial
Step-by-step explanation:
The expression is a sum of products.
Each product involves a numerical value and a product of variables to positive integer powers.
These meet the requirements for an expression to be a polynomial, so ...
the given expression is a polynomial
The polygons in each pair are similar. Find the missing side length.
Let missing one be x
If both are similar
[tex]\\ \sf\longmapsto \dfrac{20}{25}=\dfrac{16}{x}[/tex]
[tex]\\ \sf\longmapsto \dfrac{4}{5}=\dfrac{16}{x}[/tex]
[tex]\\ \sf\longmapsto 4x=16(5)[/tex]
[tex]\\ \sf\longmapsto x=\dfrac{16(5)}{4}[/tex]
[tex]\\ \sf\longmapsto x=20[/tex]
A clothing factory makes small, medium, and large sweaters. Last week, the factory made
1,612 sweaters. The factory made 3 times as many small sweaters as large sweaters. They
made 3 times as many medium sweaters as small sweaters.
How many small sweaters did the factory make last week?
This requires finding the number of small sweaters the company made last week
Number of small sweaters the company produced last week is 372
Total sweaters made = 1,612
Let
Small sweaters = 3x
Medium sweaters = x
Large sweaters = 3(3x) = 9x
Total = small + medium + large
1,612 = 3x + x + 9x
1612 = 13x
Divide by 13
x = 1612/13
Medium sweaters = x = 124
Small sweaters = 3x
= 3(124)
= 372
Read more:
https://brainly.com/question/24326559
complete explanation
Answer:
[tex]x ^{m - 3} \div x^{m - 4} \\ \frac{ {x}^{m - 3} }{ {x}^{m - 4} } \\ \frac{ {x}^{m - 3 - m + 4} }{x} \\ \frac{ {x}^{1} }{x} \\ x \: and \: x \: will \: cancel \: each \: other \: hence \: answer \: will \: be \: 1[/tex]
