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
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).
Use the discriminant to describe the roots of each equation. Then select the best description.
7x² + 1 = 5x
Answer:
Imaginary roots
Step-by-step explanation:
The discriminant of a quadratic in standard form [tex]ax^2+bx+c[/tex] is given by [tex]b^2-4ac[/tex].
Given [tex]7x^2+1=5x[/tex], subtract 5x from both sides so that the quadratic is in standard form:
[tex]7x^2-5x+1=0[/tex]
Now assign variables:
[tex]a\implies 7[/tex] [tex]b\implies -5[/tex] [tex]c\implies 1[/tex]The discriminant is therefore [tex](-5)^2-4(7)(1)=25-28=\textbf{-3}[/tex].
What does this tell us about the roots?
Recall that the discriminant is what is under the radical in the quadratic formula. The quadratic formula is used to find the solutions of a quadratic. Therefore, the solutions of this quadratic would be equal to [tex]\frac{-b\pm \sqrt{-3}}{2a}[/tex] for some [tex]b[/tex] and [tex]a[/tex]. Since the number under the radical is negative, there are no real roots to the quadratic (whenever the discriminant is negative, the are zero real solutions to the quadratic). Therefore, the quadratic has imaginary roots.
Can u please help I got 1 minnnn lefttttt
Answer:
26 cm
Step-by-step explanation:
P = 2a + 2b
a = side
b = base
Answer:
The area=base×height
=10×4
=40cm^2
perimeter=2(length+breadth)
I think to find the height Dc you use the pythagoras theorem of
Dc^2=de^2+ce^2
=√16+9
=5
therefore the perimeter will be
p=2(5+10)
=20cm
I hope this helps and sorry if it's wrong
Step by step explanation need it
Answer:
8/17
Step-by-step explanation:
The sine of an angle is defined as the opposite side to the reference angle divided by the hypotenuse.
The side opposite the angle is always the side not connected to the reference angle. In this case the opposite side = ZY
The hypotenuse = XZ
Sin(X) = ZY/XZ
Sin(X) = 1634 = 8 / 17
What is the third step in sketching the graph of a rational function
Answer:
use test numbers to find where the function is a positive and where it is negative. sketch the function's graph, plotting additional points as guides as negative. choose test numbers to t the left and right of each of these places, and find the value of the function at each test number.
Hey guys please help me please and thank you
Answer:
Option B, 5/16
Step-by-step explanation:
f(4) = 5•(1/2)⁴
= 5•(1/2⁴)
= 5•(1/16)
= 5/16
A movie theater has a seating capacity of 187. The theater charges $5.00 for children, $7.00 for students, and $12.00 of adults. There are half as many adults as there are children. If the total ticket sales was $ 1338, How many children, students, and adults attended?
___ children attended.
___ students attended.
___ adults attended.
Answer:
A) children attended=98 b) students attended=60 c)adults attended=49
Step-by-step explanation:
system%28a%2Bc%2Bx=207%2Cc%2Fa=2%2C5c%2B7x%2B12a=1498%29
Simplify and solve the system.
-
a%2B2a%2Bx=207
3a%2Bx=207
x=207-3aandc=2a
-
The revenue equation can be written in terms of just one variable, a.
10a%2B7%28207-3a%29%2B12a=1498
Solve for a;
use it to find x and c.
FURTHER STEPS
-
10a%2B1449-21a%2B12a=1498
a%2B1449=1498
a=98-49
highlight%28a=49 -------adults
-
c=2a
c=2%2A49
highlight%28c=98 -------children
-
x=207-a-c
x=207-49-98
highlight%28x=60 ---------students
Segment addition and midpoints
N is the midpoint of MO and NO is 5, so MN would also be 5
MP = MN + NP = 5 + 9 = 14
Simplify the given expression.
Answer:
8x-21
----------------------
(2x-7)(2x+7)
Step-by-step explanation:
7 4
----------- + ------------
4x^2 -49 2x+7
Factor ( notice that it is the difference of squares)
7 4
----------- + ------------
(2x)^2 - 7^2 2x+7
7 4
----------- + ------------
(2x-7)(2x+7) 2x+7
Get a common denominator
7 4(2x-7)
----------- + ------------
(2x-7)(2x+7) (2x-7)(2x+7)
Combine
7 +4(2x-7)
----------------------
(2x-7)(2x+7)
7 +8x-28
----------------------
(2x-7)(2x+7)
8x-21
----------------------
(2x-7)(2x+7)
Answer:
(8x - 21) / (2x + 7)(2x - 7)
Step-by-step explanation:
7 / (4x^2 - 49)+ 4 / (2x + 7)
= 7 / (2x + 7)(2x - 7) + 4 / (2x + 7)
LCM = (2x + 7)(2x - 7) so we have
(7 + 4(2x - 7) / (2x + 7)(2x - 7)
= (8x - 21) / (2x + 7)(2x - 7).
If Y / 4 - 12 = 3.5, what is the value of y?
Select the statement that best justifies the conclusion based on the given information.
l is in plane M,
x is on line l
Conclusion: x is in plane M.
a. A plane contains at least three points not all on the same line.
b. If two points lie in a plane, then the line containing them lies in that plane.
c. If a plane contains a line, it contains the points on the line.
d. Exactly one plane contains a given line and a point not on the line.
9514 1404 393
Answer:
c. If a plane contains a line, it contains the points on the line.
Step-by-step explanation:
The only statement relating a point on a line to the plane containing the line is the one shown above.
_____
Additional comment
Identifying true statements is a reasonable strategy for many multiple-choice questions. Another strategy that can be employed is finding the one true statement that is relevant to the question being asked.
What is 4 × 1/7 on a numberline
Answer:
4/7
Step-by-step explanation:
When you multiply by fractions you multiply the numerators and denominators
4/1 x 1/7
Anything that doesnt have anything under it always has a 1 as its denominator
If f (x) = 8X, then f (3) =
O 24
O 64
O 512
O 4,096
A 90% confidence interval is found to be (120,140). What is the margin of error?
Answer:
There is 10% error in both minimum and extreme values i.e. 120 & 140 , Error in 120 is 10% i.e. = 12, Since value can be more or less in error ∴ Error in 120 is ±12.
Which one and what do I put in the box(s)
Answer:
Option A i the right option.
First blank is 110-[tex]10\sqrt{61}[/tex] or 10(11-[tex]\sqrt{61}[/tex])
Second blank is 31.898
Let me know if anything didn't make sense.
Step-by-step explanation:
So a diagonal through a rectangle makes two triangles. The question wants to know how much walking is saved walking down the diagonal vs walking along two sides that make the diagonal. in this case the two non diagonal sides walked are 60 paces and 50 paces.
A diagonal through a rectangle specifically makes a right triangle, so to find the diagonal we can use the pythagorean theorem.
c^2 = 60^2 + 50^2
c = [tex]\sqrt{60^2 + 50^2}[/tex]
c = [tex]\sqrt{6100} = 10\sqrt{61}[/tex]
if you don't get how to simplify a radical like that let me know.
Anyway, looking at the answers you can see right away the second option says no approximation is necessary. Well, you need to approximate square root of 61, so we can say the second answer is not right. So now we need to know what to fill in for option 1.
it wants the distance saved, well we know the distance of the diagonal is [tex]10\sqrt{61}[/tex] Hopefully you can see the disctance walking the two other sides is just adding them up so 50+60=110.
Now, to find the difference, that is subtraction. So subtract the smaller number from the larger number. You do need to remember with a right triangle, the sum of the to non diagonal (hypotenuse) sides are always longer than said hypotenuse. so that's 110-[tex]10\sqrt{61}[/tex]. That is the exact form. Or you could use 10(11-[tex]\sqrt{61}[/tex]) They are the same.
Then just plug that into a calculator for a decimal approximation.
What is the median to 17,19, 20, 21, 22, 25, 29, 30, 32, 35
Answer:
23.5
Step-by-step explanation:
The median is the middle value when the numbers are put in order from smallest to largest
17,19, 20, 21, 22, 25, 29, 30, 32, 35
There are 10 numbers
17,19, 20, 21, 22, 25, 29, 30, 32, 35
The middle is between 22 and 25
(22+25)/2 = 47/2 =23.5
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
Use the equation d=z–9 to find the value of d when z=10.
d=
Step-by-step explanation:
d = z - 9
d = 10 - 9 ----> substitute
d = 1
Find the missing side length image below
Answer:
40
Step-by-step explanation:
Based on the Proportional Transversal Theorem, the three parallel lines hat intersects the two transversals, divides the transversal lines proportionally.
Therefore, we would have the following ratio:
28/35 = ?/50
Cross multiply
35*? = 50*28
35*? = 1,400
Divide both sides by 35
? = 1400/35
? = 40
A family is thinking about buying a new house
costing 380 000$. They must pay 110 000$ down and the rest is to
be amortized over 25 years in equal monthly payments. If money
costs 7% compounded monthly
(A)What will their monthly payment be?
(B)What will be unpaid balance after 20 years?
(C)How much total interest will be paid over the 25 years?
Answer:
a.) 1908.30
b.) 96373.15
c.)302491.15
unrounded answers below
Step-by-step explanation:
The amount that is to be loaned out is 380000-110000=270000
The effective montly rate is .07/12=.005833333
a.)
[tex]270000=x(\frac{1-(1+.005833333)^{-(25*12)}}{.005833333})=1908.303833[/tex]
b.)
use what is called the prospective method (the outstanding loan balance at time n is equal to the present value of the remaining payments)
[tex]1908.303833(\frac{1-(1+.005833333)^{-(25*12-20*12)}}{.005833333})=96373.14775[/tex]
c.)
total paid= 1908.303833*12*25=572491.1499
amount of loan: 270000
Total interest paid:
572491.1499-270000=302491.1499
Find the value of x.
X 9 9 7 x = [?]
Consider an x distribution with standard deviation o = 34.
(a) If specifications for a research project require the standard error of the corresponding distribution to be 2, how
large does the sample size need to be?
B) If specifications for a research project require the standard error of the corresponding x distribution to be 1, how large does the sample size need to be?
Part (a)
The standard error (SE) formula is
[tex]\text{SE} = \frac{\sigma}{\sqrt{n}}\\\\[/tex]
where n is the sample size. We're given SE = 2 and sigma = 34, so,
[tex]\text{SE} = \frac{\sigma}{\sqrt{n}}\\\\2 = \frac{34}{\sqrt{n}}\\\\2\sqrt{n} = 34\\\\\sqrt{n} = \frac{34}{2}\\\\\sqrt{n} = 17\\\\n = 17^2\\\\n = 289\\\\[/tex]
So we need a sample size of n = 289 to have an SE value of 2.
Answer: 289========================================================
Part (b)
We'll use SE = 1 this time
[tex]\text{SE} = \frac{\sigma}{\sqrt{n}}\\\\1 = \frac{34}{\sqrt{n}}\\\\1*\sqrt{n} = 34\\\\\sqrt{n} = 34\\\\n = 34^2\\\\n = 1156\\\\[/tex]
Because we require greater precision (i.e. a smaller SE value), the sample size must be larger to account for this. In other words, as SE goes down, then n must go up, and vice versa.
Answer: 1156What is a corresponding pair for f(-7)=5
Answer:
An ordered pair for a function f(x) looks like (x, f(x)). So the ordered pair here would be (5, f(5)) or (5, 7). Either one would work, as they are the same.
Suppose you have 3 bags. Two of them contain a single $10 bill, and the third contains a single $5 bill. Suppose you pick one of these bags uniformly at random. You then add a $5 bill to the bag, so it now contains two bills. The bag is shaken, and you randomly draw a bill from the bag without looking into the bag. Suppose it turns out to be a $5 bill. If a you draw the remaining bill from the bag, what is the probability that it, too, is a $5 bill
Answer:
1/2
Step-by-step explanation:
Number of bags = 3
number of bags with $10 bill initially = 2
number of bags with $5 bill initially = 1
assume :
event you pick a $5 bill at first draw = A
event you pick a $5 bill at second draw = B
hence : P ( A n B ) = 1/3 * 1 = 1/3
P( A ) = ( 1/3 * 1 ) + ( 1/3 * 1/2 + 1/3 * 1/2 ) = 2/3
therefore P( that the second drawn bill is $5 )
P( B | A ) = P(A n B ) / P ( A )
= (1/3) / (2/3) = 1/2
The probability that it, too, is a $ 5 bill is 33.33%.
Since you have 3 bags, and two of them contain a single $ 10 bill, and the third contains a single $ 5 bill, supposing you pick one of these bags uniformly at random and you then add a $ 5 bill to the bag, so it now contains two bills, and the bag is shaken, and you randomly draw a bill from the bag without looking into the bag, supposing it turns out to be a $ 5 bill, if a you draw the remaining bill from the bag, to determine what is the probability that it, too, is a $ 5 bill, the following calculation must be performed:
3 bags = 2 with a 10 bill and 1 with a 5 bill 1/3 = 0.3333 0.3333 x 100 = 33.33
Therefore, the probability that it, too, is a $ 5 bill is 33.33%.
Learn more in https://brainly.com/question/13243988
Find the interquartile range for a data set having the five-number summary: 4.6, 14.3, 19.7, 26.1, 31.2
======================================================
Explanation:
The five number summary is the set of these items, in this exact order
Min = smallest valueQ1 = first quartileMedian = middle most numberQ3 = third quartileMax = largest valueSo with the five number summary 4.6, 14.3, 19.7, 26.1, 31.2, we see that
Q1 = 14.3 and Q3 = 26.1
Subtracting these two values gets us the IQR (interquartile range)
IQR = Q3 - Q1
IQR = 26.1 - 14.3
IQR = 11.8
Rose plans to have two children but doesn’t know if they will be boy-boy, girl-girl, girl-boy, or boy-girl. What is the probability that she will have boy-girl?
Answer:
1/4
Step-by-step explanation:
There are four probabilities and the probability of her having 1 of the 4 probabilities is 1/4
The equation cos(35•) = a/25 can be used to find the length of BC what is the length of BC round to the nearest tenth
What is the equation of a line that passes through the point (5,-3) and has a slope of -2
Answer:
y=-2x+7
Step-by-step explanation:
The Slope is obviously -2, and just add a random y and play around with it until it goes through the point (5,-3)
Solve the above quadratic equation
Answer:
r = 1
Step-by-step explanation:
Find the intersection.
r = 1
r = 3
r = -1
r = 1
Answer:
r=3, r=1, r= -1
Step-by-step explanation:
48r^3-144r^2-48r=-144
48r^3-144r^2-48r +144 =-144 + 144
48r^3-144r^2-48r+144=0
48(r-3)(r+1)(r-1)
r-3=0 r+1=0 r-1=0
r=3, r=1, r= -1
A cylindrical vase has a diameter of 4 inches. At the bottom of the vase, there are 6 marbles, each of diameter 3 inches. The vase is filled with water up to a height of 8 inches. Which of the following could be used to calculate the volume of water in the vase?
π(2in)^2(8in) − 6(four over threeπ(1.5in)^3)
π(8in)^2(2in) − 6(four over threeπ(1.5in)^3)
π(2in)^2(8in) − 1.5(four over threeπ(6in)^3)
π(8in)^2(2in) − 1.5(four over threeπ(6in)^3)
The volume of the water is: [tex]\pi (2)^2(8) - 6 (\frac{4}{3} \pi (1.5)^3)[/tex]
The volume of a cylinder is;
[tex]V = \pi r^2h[/tex]
For the cylinder, we have:
[tex]d = 4[/tex] -- diameter
[tex]h = 8[/tex] --- height of the water in the cylinder
The radius of the cylinder is:
[tex]r =d/2 = 4/2 = 2[/tex]
So, the volume is:
[tex]V = \pi * 2^2 * 8[/tex]
[tex]V = \pi * (2)^2 (8)[/tex]
For the 6 marbles, we have:
[tex]d = 3[/tex] --- the diameter of each
The shape of the marble is a sphere. So, the volume of 1 marble is:
[tex]V = \frac{4}{3}\pi r^3[/tex]
The radius of 1 marble is:
[tex]r = d/2 = 3/2 = 1.5[/tex]
So, the volume of 1 marble is:
[tex]V_1 = \frac{4}{3} * \pi * (1.5)^3[/tex]
Multiply both sides by 6 to get the volume of the 6 marbles
[tex]6 * V_1 = 6 * \frac{4}{3} * \pi * (1.5)^3[/tex]
[tex]6V_1 = 6 * \frac{4}{3} * \pi * (1.5)^3[/tex]
[tex]6V_1 = 6 (\frac{4}{3} \pi (1.5)^3)[/tex]
Recall that the volume of the cylinder is:
[tex]V = \pi * (2)^2 (8)[/tex]
The volume of the water in the marble is the difference between the volume of the cylinder and the volume of the 6 marbles
So, we have:
[tex]Volume = \pi (2)^2(8) - 6 (\frac{4}{3} \pi (1.5)^3)[/tex]
The expression [tex]V = \pi \cdot (2\,in)^{2}\cdot (8\,in) -6\cdot \left[\frac{4\pi}{3}\cdot (1.5\,in)^{3} \right][/tex] can be used to calculate the volume of water in the vase.
As vase is of cylindrical form and the six marbles are spherical, we shall derived an expression from volume formulas respective to Cylinder and Spheres. Firstly, we know that volume of water in the vase is equal to the Volume of the vase minus the volume occupied by the six marbles, that is to say:
[tex]V = V_{v}-6\cdot V_{m}[/tex] (1)
Where:
[tex]V_{v}[/tex] - Volume of the vase, in cubic inches.
[tex]V_{m}[/tex] - Volume of the marble, in cubic inches.
[tex]V[/tex] - Volume of water in the vase, in cubic inches.
Then, we expand (1) by volume formulas for the cylinder and sphere:
[tex]V = \pi\cdot R^{2}\cdot H - 6\cdot \left(\frac{4\pi}{3} \cdot r^{3} \right)[/tex] (2)
Where:
[tex]R[/tex] - Radius of the vase, in inches.
[tex]H[/tex] - Height of the vase, in inches.
[tex]r[/tex] - Radius of the marble, in inches.
If we know that [tex]R = 2\,in[/tex], [tex]H = 8\,in[/tex], [tex]r = 1.5\,in[/tex], then the following expression can be used to calculate the volume of water in the base:
[tex]V = \pi \cdot (2\,in)^{2}\cdot (8\,in) -6\cdot \left[\frac{4\pi}{3}\cdot (1.5\,in)^{3} \right][/tex]
In a nutshell, the expression [tex]V = \pi \cdot (2\,in)^{2}\cdot (8\,in) -6\cdot \left[\frac{4\pi}{3}\cdot (1.5\,in)^{3} \right][/tex] can be used to calculate the volume of water in the vase.
