Hey there! I'm happy to help!
We want to isolate y on one side of the equation to see what it equals. To do this, we use inverse operations to cancel out numbers on the y side and find the correct value.
1/3y+4=16
We subtract 4 from both sides, canceling out the +4 on the right but keeping the same y-value by doing the same to the other side.
1/3y=12
We divide both sides by 1/3 (which is multiplying both sides by 3) which will cancel out the 1/3 and tell us what y is equal to.
y=36
Now you know how to solve basic equations! Have a wonderful day! :D
The scores for all the Algebra 1 students at Miller High on a test are normally distributed with a mean of 82 and a standard deviation of 7. What percent of students made scores above 89?
Answer:
15.7% of students made above an 89.
Step-by-step explanation:
If the data is normally distributed, the standard deviation is 7, and the mean is 82, then about 68.2% of students made between 75 and 89. 13.6% made between 90 and 96, and 2.1% made over 96. 13.6+2.1=15.7%
Consider the surface f(x,y) = 21 - 4x² - 16y² (a plane) and the point P(1,1,1) on the surface.
Required:
a. Find the gradient of f.
b. Let C' be the path of steepest descent on the surface beginning at P, and let C be the projection of C' on the xy-plane. Find an equation of C in the xy-plane.
c. Find parametric equations for the path C' on the surface.
Answer:
A) ( -8, -32 )
Step-by-step explanation:
Given function : f (x,y) = 21 - 4x^2 - 16y^2
point p( 1,1,1 ) on surface
Gradient of F
attached below is the detailed solution
Vu is three times as old as Wu. In 25 years Wu will be twice as old as Vu. How old is Vu now?
Answer: Vu is 15 years old now.
Step-by-step explanation:
Let present age of WU be x.
Then, the present age of Vu = 3x
Also, After 25 years
Age of Wu = x+25
According to the question:
[tex](x+25)=2(3x)\\\\\Rightarrow\ x+25=6x\\\\\Rightarrow\5x=25\\\\\Rightarrow\ x=5[/tex]
Present age of Vu = 3(5) = 15
Hence, Vu is 15 years old now.
Answer:
j
Step-by-step explanation:j
Log 1/10 how do you convert this without a calculator
Answer:
log(1/10) = -1
Step-by-step explanation:
Use the law of exponents and the meaning of logarithm.
1/10 = 10^-1
log(10^x) = x
So, you have ...
log(1/10) = log(10^-1)
log(1/10) = -1
the amount of gas in sarahs car is uniformly distributed between 1 and 16 gallons. Calculate the probability that the amount of gas is exactly 7 gallons
Answer:
The probability that the amount of gas in Sarah's car is exactly 7 gallons is 0.067.
Step-by-step explanation:
Let the random variable X represent the amount of gas in Sarah's car.
It is provided that [tex]X\sim Unif(1, 16)[/tex].
The amount of gas in a car is a continuous variable.
So, the random variable X follows a continuous uniform distribution.
Then the probability density function of X is:
[tex]f_{X}(x)=\frac{1}{b-a};\ a<X<b[/tex]
For a continuous probability distribution the probability at an exact point is 0.
So, to compute the probability that the amount of gas in Sarah's car is exactly 7 gallons use continuity correction on both sides:
P (X = 7) = P (7 - 0.5 < X < 7 + 0.5)
= P (6.5 < X < 7.5)
[tex]=\int\limits^{7.5}_{6.5} {\frac{1}{16-1}} \, dx \\\\=\frac{1}{15}\times |x|^{7.5}_{6.5}\\\\=\frac{1}{15}\times (7.5-6.5)\\\\=\frac{1}{15}\\\\=0.0666667\\\\\approx 0.067[/tex]
Thus, the probability that the amount of gas in Sarah's car is exactly 7 gallons is 0.067.
15 POINTS AND BRAINLIEST JUST HELP ME PLZZZZZ 4x^2 + 28x + 49 = 0 Rewrite equation (x + __ )^2 = __
Answer:
[tex]\boxed{(x+7)^2 =-3x^2-14x}[/tex]
Step-by-step explanation:
[tex]4x^2 + 28x + 49 = 0[/tex]
[tex]\sf Subtract \ 3x^2 \ and \ 14x \ from \ both \ sides.[/tex]
[tex]4x^2 + 28x + 49 -3x^2-14x= 0-3x^2-14x[/tex]
[tex]x^2 + 14x + 49 = -3x^2-14x[/tex]
[tex]\sf Factor \ left \ side \ of \ the \ equation.[/tex]
[tex](x+7)^2 =-3x^2-14x[/tex]
Answer:
(x+7)² = -3x² -14x
Step-by-step explanation:
4x^2 + 28x + 49 = 0
Subtract 3x² and 14x from each sides.
x^2 + 14x + 49 = -3x² -14x
Next step will be factoring.
(x+7)² = -3x² -14x
A pharmacist needs 16 liters of a 4% saline solution. He has a 1% solution and a 5% solution available. How many liters of the 1% solution and how many liters of the 5% solution should he mix to make the 4% solution?
x = liters of 1% solution
y = liters of 5% solution
x + y = 16
0.01x + 0.05y = 0.04*16 = 0.64
y = 16 - x
0.01x + 0.05(16 - x) = 0.64
0.01x + 0.8 - 0.05x = 0.64
0.16 = 0.04x
x = 4
y = 12
Find the (a) mean, (b) median, (c) mode, and (d) midrange for the data and then (e) answer the given question. Listed below are the weights in pounds of 1111 players randomly selected from the roster of a championship sports team. Are the results likely to be representative of all players in that sport's league?
278 303 186 292 276 205 208 236 278 198 208
a. Find the mean.
The mean is ? pound(s).
(Type an integer or a decimal rounded to one decimal place asneeded.)
b. Find the median.
The median is ? pound(s).
(Type an integer or a decimal rounded to one decimal place asneeded.)
c. Find the mode.
Select the correct choice below and, if necessary, fill in the answer box to complete your choice.
A. The mode(s) is(are) ? pound(s).
(Type an integer or a decimal. Do not round. Use a comma to separate answers as needed.)
B. There is no mode.
d. Find the midrange.
The midrange is ? pound(s).
(Type an integer or a decimal rounded to one decimal place asneeded.)
e. Are the results likely to be representative of all players in that sport's league?
A. The results are not likely to be representative because the median is not equal to the mode.
B. The results are likely to be representative because a championship team is most likely representative of the entire league.
C. The results are not likely to be representative because the median is not equal to the mean.
D. The results are not likely to be representative because the championship team may not be representative of the entire league.
Answer:
Mean= 242.5 pounds
Median= 236 pounds
Mode= 208 and 278 pounds
Range=117 pounds
Mid-range= 58.5 pounds
B. The results are likely to be representative because a championship team is most likely representative of the entire league.
Step-by-step explanation:
278 303 186 292 276 205 208 236 278 198 208
Arranged in ascending order is
186 198 205 208 208 236 276 278 278 292 303
Mean = (186 +198+ 205+ 208 +208 +236 + 276+ 278 +278+ 292 +303)/11
Mean =2668/11
Mean= 242.5 pounds
Median = the middle number
Median= 236 pounds
Mode = highest occuring number(s)
Mode= 208 and 278 pounds
Range= highest number- smallest number
Range=303-186
Range=117 pounds
Mid-range= range/2
Mid-range= 117/2
Mid-range= 58.5 pounds
Volume 1 (3)3 = 367
SSCE/JME-TYPE OF
2
The area of an equilateral triangle of side 8 cm is
A. 16V3 cm? B. 32/3 cm
B.
48 cm
cm?
D.
36V3 cm
A
parallelogram
of area 425 cmhas a height o
Answer:
[tex]A.\ 16\sqrt3\ cm^2[/tex] is the correct answer.
Step-by-step explanation:
Given that:
Side of an equilateral triangle = 8 cm
To find:
Area of the triangle will be:
[tex]A.\ 16\sqrt3\ cm^2[/tex]
[tex]B.\ \dfrac{32}{3} cm^2[/tex]
[tex]C.\ 48\ cm^2[/tex]
[tex]D.\ 36\sqrt3\ cm^2[/tex]
Solution:
First of all, let us have a look at the formula for area of an equilateral triangle:
[tex]A =\dfrac{\sqrt3}{4}a^2[/tex]
Where [tex]a[/tex] is the side of equilateral triangle and an equilateral triangle is a closed 3 sided structure in 2 dimensions which has all 3 sides equal to each other.
Here, we are given that side, [tex]a=8\ cm[/tex]
Putting the value in formula:
[tex]A =\dfrac{\sqrt3}{4}\times 8^2\\\Rightarrow A =\dfrac{\sqrt3}{4}\times 64\\\Rightarrow A =\sqrt3\times 16\\OR\\\Rightarrow \bold{A =16\sqrt3\ cm^2}[/tex]
Hence, [tex]A.\ 16\sqrt3\ cm^2[/tex] is the correct answer.
I am performing a before and after evaluation on 30 students who have taken a keyboarding class. I want to see if the course improved their words per minute keyed.
Required:
a. State the Null and Alternate Hypothesis.
b. The statistic that I would use is:_________
c. What would my t critical be for this calculation at a 0.10 level of significance?
d. If my t calculated = 1.62, would I reject or fail to reject the null hypothesis?
Answer:
a)
H₀ : µd = 0
H₁ : µd < 0
b)
The test statistic is
tₙ₋₁ = α / s√n
c)
at 0.10 level of significance,
tₙ₋₁ , ₐ
t₃₀₋₁ , ₀.₁₀ = t₂₉, ₀.₁₀ = 1.311
d)
given that T(critical) = 1.62
∴ T(critical) = 1.62 > t₂₉, ₀.₁₀ = 1.311
at 10% level of significance,
REJECT H₀
Since 1.62 > 1.311, we can reject the null hypothesis.
Simple math! What is the issue with my work? I got it wrong.
Answer:
x = 6
Step-by-step explanation:
In the third line of the solution on right side of the equal sign, middle term should be 8x instead of 4x.
The final value of x will be 6.
[tex] PQ^2 + QO^2 = PO^2 \\
x^2 + 8^2 = (4+x)^2 \\
x^2 + 64 = 16 + 8x + x^2 \\
64 = 16 + 8x \\
64 - 16 = 8x \\
48 = 8x \\
6 = x\\[/tex]
If the sum of the daily unpaid balances is $7,812 over a 31-day billing cycle, what is the average daily balance?
Answer:
252
Step-by-step explanation:
Divide 7812 by 31 and we get the average daily answer... Hope this helps!!
Isreal spends the most time on social media with a total of 11.1.peru has a total of 8.3 how much more time does israel spend on social media
Answer:
2.8
Step-by-step explanation:
11.1-8.3=2.8
HOPE I HELPED
PLS MARK BRAINLIEST
DESPERATELY TRYING TO LEVEL UP
✌ -ZYLYNN JADE ARDENNE
JUST A RANDOM GIRL WANTING TO HELP PEOPLE!
PEACE!
Please answer my question
Step-by-step explanation:
The inequality shows by line is
i) 1<=x<=6
OR,
x is an positive integer.
Ellen baked 115 cookies and shared them equally with her 23 classmates. How many whole cookies each can Ellen and her classmates have?
Step-by-step explanation:
Ellen - 115/23
Classmates and Ellen got = 5 each
Two friends are standing at opposite corners of a rectangular courtyard. The dimensions of the courtyard are 12 ft. by 25 ft. How far apart are the friends?
Answer:
27.73 feet
Step-by-step explanation:
Use the Pythagorean theorem. It easiest to think of the distance between the two friends as a triangle in the rectangle. One side is 12ft and the other is 25ft.
12^2+25ft^2=769
The square root of 769 is 27.73
Answer:
27.73 Ft
Step-by-step explanation:I took the test
Assume a bank loan requires an interest payment of $85 per year and a principal payment of $1,000 at the end of the loan's eight-year life. What would be the present value of this loan if it carried a 10% interest rate?
Answer:
The present value is [tex]PV = \$ 396,987[/tex]
Step-by-step explanation:
From the question we are told that
The interest payment per year is [tex]C = \$ 85[/tex]
The principal payment is [tex]P = \$ 1000[/tex]
The duration is n = 8 years
The interest rate is [tex]r = 10\% = 0.10[/tex]
The present value is mathematically represented as
[tex]PV = [ \frac{C}{r} * [1 - \frac{1 }{ (1 +r)^n} ] + \frac{P}{(1 + r)^n} ][/tex]
substituting values
[tex]PV = [ \frac{85}{0.10} * [1 - \frac{1 }{ (1 +0.10)^8} ] + \frac{1000}{(1 + 0.10)^ 8} ][/tex]
[tex]PV = \$ 396,987[/tex]
consider the bevariate data below about Advanced Mathematics and English results for a 2015 examination scored by 14 students in a particular school.The raw score of the examination was out of 100 marks.
Questions:
a)Draw a scatter graph
b)Draw a line of Best Fit
c)Predict the Advance Mathematics mark of a student who scores 30 of of 100 in English.
d)calculate the correlation using the Pearson's Correlation Coefficient Formula
e) Determine the strength of the correlation
Answer:
Explained below.
Step-by-step explanation:
Enter the data in an Excel sheet.
(a)
Go to Insert → Chart → Scatter.
Select the first type of Scatter chart.
The scatter plot is attached below.
(b)
The scatter plot with the line of best fit is attached below.
The line of best fit is:
[tex]y=-0.8046x+103.56[/tex]
(c)
Compute the value of x for y = 30 as follows:
[tex]y=-0.8046x+103.56[/tex]
[tex]30=-0.8046x+103.56\\\\0.8046x=103.56-30\\\\x=\frac{73.56}{0.8046}\\\\x\approx 91.42[/tex]
Thus, the Advance Mathematics mark of a student who scores 30 out of 100 in English is 91.42.
(d)
The Pearson's Correlation Coefficient is:
[tex]r=\frac{n\cdot \sum XY-\sum X\cdot \sum Y}{\sqrt{[n\cdot \sum X^{2}-(\sum X)^{2}][n\cdot \sum Y^{2}-(\sum Y)^{2}]}}[/tex]
[tex]=\frac{14\cdot 44010-835\cdot 778}{\sqrt{[14\cdot52775-(825)^{2}][14\cdot 47094-(778)^{2}]}}\\\\= -0.7062\\\\\approx -0.71[/tex]
Thus, the Pearson's Correlation Coefficient is -0.71.
(e)
A correlation coefficient between ± 0.50 and ±1.00 is considered as a strong correlation.
The correlation between Advanced Mathematics and English results is -0.71.
This implies that there is a strong negative correlation.
The length of a rectangle is three times its width. If the perimeter of the rectangle is 160 cm, what are the dimensions of this rectangle?
Answer:
The dimensions or Area of the rectangle is 1200cm².
Plzz help i really need help..
Answer:
D. neither.
Step-by-step explanation:
A function is when one x-value only has one corrisponding y-value.
The answer it's D. Neither
According to psychologists, IQs are normally distributed, with a mean of 100 and a standard deviation of 15 . a. What percentage of the population has IQs between 85 and 100 ?
=
Graphing an integer function and finding its range for a given...
The function h is defined as follows for the domain given.
h(x) = 2 -2x, domain = {-3, -2, 1, 5}
Write the range of h using set notation. Then graph h.
Answer:
Step-by-step explanation:
● h(x) = 2-2x
The domain is {-3,-2,1,5}
● h(-3) = 2-2×(-3) = 2+6 = 8
● h(-2) = 2 -2×(-2) = 2+4 = 6
● h(1) = 2-2×1 = 2-2 = 0
● h(5) = 2-2×5 = 2-10 = -8
The range is {-8,0,6,8}
A bike wheel is 26 inches in diameter. What is the bike wheel's diameter in millimeters (1 inch = 25.4 millimeters)?
Answer:
Diameter of wheel in millimetres is 660.4
Step-by-step explanation:
Diameter of wheel in inches = 26
given
1 inch = 25.4 millimeters
multiplying RHS and LHS by 26
26*1 inch = 26*25.4 millimeters
=>26 inch = 660.4 mm.
Thus, diameter of wheel in millimetres is 660.4
How many numbers from 10 to 99 have a tens place exactly 3 times greater than their ones place? PLZZZ answer this question . I will be very happy whoever answers this I will give u brainliest too.
Answer:
45
Step-by-step explanation:
2 digit number starts from 10 ends at 99
between 10 and 19 there is only one number whose tens digit is more than ones digit.
that is 10
between 20 and 29 there are two numbers
20 and 21
like the same
between 30 and 39 there are 3 numbers
10–19. 1
20–29. 2
30–39. 3
40–49. 4
50–59. 5
60–69. 6
70–79. 7
80–89. 8
99–99. 9
sum of first n natural numbers is n(n+1)/2
9(9+1)/2=45
Three numbers between 10 and 99 have tens places that are precisely three times larger than their one's places.
What is Place value?The foundation of our whole number system is place value. In this approach, the value of a digit in a number is determined by where it appears in the number.
The tens digit must be three times larger than the units digit in order to meet the requirement. The units digit can have one of the following values: 0, 1, 2, 3, 4, 5, 6, 7, 8, or 9.
Since we are seeking two-digit integers, it is not possible if the unit digit is zero for the tens digit also be zero.
In the case when the unit digit is 1, the tens digit must be 3, resulting in the number 31. Similar to the previous example, if the unit digit is 2, the tens digit must be 6, resulting in the number 62.
As we proceed, we discover the following integers meet the condition:
31, 62, 93
Therefore, there are three numbers from 10 to 99 that have a tens place exactly 3 times greater than their one's place.
Learn more about place values here:
https://brainly.com/question/27734142
#SPJ3
Nine students took the SAT. Their scores are listed below. Later on, they read a book on test preparation and retook the SAT. Their new scores are listed below. Test the claim that the book had no effect on their scores.Use α=0.05. Assume that the distribution is normally distributed. Student 1 2 3 4 5 6 7 8 9 Scores before reading book 72 0 86 0 850 88 0 86 0 710 85 0 1200 95 0 Scores after reading book 74 0 86 0 840 92 0 89 0 720 84 0 1240 97 0 Nine students took the SAT. Their scores are listed below. Later on, they read a book on test preparation and retook the SAT. Their new scores are listed below. Test the claim that the book had no effect on their scores. Use α = 0.05. Assume that the distribution is normally distributed. Student 1 2 3 4 5 6 7 8 9 Scores before reading book 72 0 86 0 850 88 0 86 0 710 85 0 1200 95 0 Scores after reading book 74 0 86 0 840 92 0 89 0 720 84 0 1240 97 0
Answer:
t= 0.4933
t ≥ t ( 0.025 ,8 ) = 2.306
Since the calculated value of t= 0.4933 is less than t ( 0.025 ,8 ) = 2.306 therefore we accept the null hypothesis at 5 % significance level . On the basis of this we conclude that the book had no effect on their scores.
Step-by-step explanation:
We state our null and alternative hypotheses as
H0: ud= 0 Ha: ud≠0
The significance level is set at ∝= 0.05
The test statistic under H0 is
t= d`/ sd/√n
which has t distribution with n-1 degrees of freedom
The critical region is t ≥ t ( 0.025 ,8 ) = 2.306
Computations
Student Scores before Scores after Difference d²
reading book ( after minus before)
1 720 740 20 400
2 860 860 0 0
3 850 840 -10 100
4 880 920 40 1600
5 860 890 30 900
6 710 720 10 100
7 850 840 -10 100
8 1200 1240 40 1600
9 950 970 20 40
∑ 6930 8020 140 4840
d`= ∑d/n= 140/9= 15.566
sd²= 1/8( 4840- 140²/9) = 1/8 (4840 - 2177.778) = 2662.22/8= 332.775
sd= 18.2422
t= 3/ 18.2422/ √9
t= 0.4933
Since the calculated value of t= 0.4933 is less than t ( 0.025 ,8 ) = 2.306 therefore we accept the null hypothesis at 5 % significance level . On the basis of this we conclude that the book had no effect on their scores.
I need help pls. Algebra
Answer:
The answer is option AStep-by-step explanation:
f(x) = (x+1)³ + 4
To find f-¹(x) equate f(x) to y
That's
y = (x+1)³ + 4
Next interchange the terms x becomes y and y becomes x
That's
x = ( y+1)³ + 4
Make y the subject
(y+1)³ = x - 4
Find the cube root of both sides
That's
[tex]y + 1 = \sqrt[3]{x - 4} [/tex]
Send 1 to the right side of the equation
That's
[tex]y = \sqrt[3]{x - 4} - 1[/tex]
So we have the final answer as
[tex]f ^{ - 1} (x) = \sqrt[3]{x - 4} - 1[/tex]
Hope this helps you
Answer:
option 1
Step-by-step explanation:
f(x)=(x+1)³+4
to find the inverse interchange the variable and solve for y
inverse f(x)=(y+1)³+4
x=(y+1)³+4
x-4=(y+1)³
y+1=∛x-4
y=∛x-4 -1
Decide all proper subsets of A { 8 ,7 ,6 ,5 ,4 ,3 ,2 ,1} = A 1- { 4 ,3 ,2 ,1} 2- { } 3- { 9 ,8 ,7 } 4- { 11 ,2} 5- { 5 }
Answer:
A, E
Step-by-step explanation:
There should be 2^8-1 proper subsets of A. Its every one besides { }
Find the area of the shape shown below.
2
2
nd
2
Need help Plz hurry and answer!!!
Answer:
=6 units squared
Step-by-step explanation:
area=1/2h(a+b)
=1/2×2(4+2)
=6
Suppose you have read two different books on world war 2 and each book has different arguments about how the war started which of the following sources provides the best support for the authors arguments
Answer:
Well this is my opinion I would try to compared both them and see if they have something familiar in their arguments. If not I would try to view their different point of view and write your own opinion about it. I would check out another book about the World War 2 because there's infinite of books about it.
Among a simple random sample of 331 American adults who do not have a four-year college degree and are not currently enrolled in school, 48% said they decided not to go to college because they could not afford school.
Part II: Exercise 6.16 presents the results of a poll where 48% of 331 Americans who decide to not go to college do so because they cannot afford it.
#1: Calculate a 90% confidence interval for the proportion of Americans who decide to not go to college because they cannot afford it, and interpret the interval in context.
(a) lower bound: ______ (please round to four decimal places)
(b) upper bound: _____ (please round to four decimal places)
#2: Interpret the confidence interval in context:
(A) We can be 90% confident that our confidence interval contains the sample proportion of Americans who choose not to go to college because they cannot afford it
(B) 90% of Americans choose not to go to college because they cannot afford it
(C) We can be 90% confident that the proportion of Americans who choose not to go to college because they cannot afford it is contained within our confidence interval
#3: Suppose we wanted the margin of error for the 90% confidence level to be about 1.5%. How large of a survey would you recommend?
(a) A survey should include at least ________ people.
Answer:
(1) Therefore, a 90% confidence interval for the proportion of Americans who decide to not go to college because they cannot afford it is [0.4348, 0.5252].
(2) We can be 90% confident that the proportion of Americans who choose not to go to college because they cannot afford it is contained within our confidence interval
(3) A survey should include at least 3002 people if we wanted the margin of error for the 90% confidence level to be about 1.5%.
Step-by-step explanation:
We are given that a simple random sample of 331 American adults who do not have a four-year college degree and are not currently enrolled in school, 48% said they decided not to go to college because they could not afford school.
Firstly, the pivotal quantity for finding the confidence interval for the population proportion is given by;
P.Q. = [tex]\frac{\hat p-p}{\sqrt{\frac{\hat p(1-\hat p)}{n} } }[/tex] ~ N(0,1)
where, [tex]\hat p[/tex] = sample proportion of Americans who decide to not go to college = 48%
n = sample of American adults = 331
p = population proportion of Americans who decide to not go to
college because they cannot afford it
Here for constructing a 90% confidence interval we have used a One-sample z-test for proportions.
So, 90% confidence interval for the population proportion, p is ;
P(-1.645 < N(0,1) < 1.645) = 0.90 {As the critical value of z at 5% level
of significance are -1.645 & 1.645}
P(-1.645 < [tex]\frac{\hat p-p}{\sqrt{\frac{\hat p(1-\hat p)}{n} } }[/tex] < 1.645) = 0.90
P( [tex]-1.645 \times {\sqrt{\frac{\hat p(1-\hat p)}{n} } }[/tex] < [tex]\hat p-p[/tex] < [tex]1.645 \times {\sqrt{\frac{\hat p(1-\hat p)}{n} } }[/tex] ) = 0.90
P( [tex]\hat p-1.645 \times {\sqrt{\frac{\hat p(1-\hat p)}{n} } }[/tex] < p < [tex]\hat p+1.645 \times {\sqrt{\frac{\hat p(1-\hat p)}{n} } }[/tex] ) = 0.90
90% confidence interval for p = [ [tex]\hat p-1.645 \times {\sqrt{\frac{\hat p(1-\hat p)}{n} } }[/tex] , [tex]\hat p+1.645 \times {\sqrt{\frac{\hat p(1-\hat p)}{n} } }[/tex] ]
= [ [tex]0.48 -1.96 \times {\sqrt{\frac{0.48(1-0.48)}{331} } }[/tex] , [tex]0.48 +1.96 \times {\sqrt{\frac{0.48(1-0.48)}{331} } }[/tex] ]
= [0.4348, 0.5252]
(1) Therefore, a 90% confidence interval for the proportion of Americans who decide to not go to college because they cannot afford it is [0.4348, 0.5252].
(2) The interpretation of the above confidence interval is that we can be 90% confident that the proportion of Americans who choose not to go to college because they cannot afford it is contained within our confidence interval.
3) Now, it is given that we wanted the margin of error for the 90% confidence level to be about 1.5%.
So, the margin of error = [tex]Z_(_\frac{\alpha}{2}_) \times \sqrt{\frac{\hat p(1-\hat p)}{n} }[/tex]
[tex]0.015 = 1.645 \times \sqrt{\frac{0.48(1-0.48)}{n} }[/tex]
[tex]\sqrt{n} = \frac{1.645 \times \sqrt{0.48 \times 0.52} }{0.015}[/tex]
[tex]\sqrt{n}[/tex] = 54.79
n = [tex]54.79^{2}[/tex]
n = 3001.88 ≈ 3002
Hence, a survey should include at least 3002 people if we wanted the margin of error for the 90% confidence level to be about 1.5%.
