A friend of yours was interested in computing a confidence interval for the mean student debt accumulated by NC State graduates during their undergraduate education. They collected a random sample of 40 students, and asked each how much student debt they had; all responded and responded honestly. A histogram of the data indicated it was normally distributed. They computed a 95% confidence interval of ($36,400, $41,650). However, they were unsatisfied with the margin of error, wanting a more precise interval. Referring to their ST 311 notes, they noted that in order to reduce the margin of error by half, they needed to increase their sample size by a factor of 4. So, they collected another random sample of 160 students and found another 95% confidence interval, which was much narrower, having a margin of error of $1,318. They are satisfied with the precision of the confidence interval, but are a little confused : it’s not quite half the original margin of error. Explain why the margin of error wasn’t quite reduced by a factor of 0.5. Be specific.

Answers

Answer 1

Answer:

Explained below.

Step-by-step explanation:

The (1 - α)% confidence interval for the population mean is:

[tex]CI=\bar x\pm z_{\alpha/2}\times\frac{\sigma}{\sqrt{n}}[/tex]

The margin of error for this interval is:

[tex]MOE= z_{\alpha/2}\times\frac{\sigma}{\sqrt{n}}[/tex]

The factors affecting the MOE are:

The sample size (n) is inversely proportional to the MOE, thus increasing n decreases the MOE and vice-versa. Variance (σ²) is the square of S.D. So if we increase σ² then σ increases.  Since σ is directly proportional to MOE, increasing σ increases MOE. The confidence level is the value of (1 – α). If we increase the confidence level then the critical value increases and thus MOE also increases.

Since the population standard deviation is not provided it is obvious the sample standard deviation is used to estimate the value of σ.

On increasing the value of σ the MOE will also increase.

As the sample size is inversely proportional, increasing the sample size by a factor of 4 will reduce the margin of error by half. But since σ is also increasing there are two factors affecting the MOE together.

Therefore reducing the MOE by more than half the original value.


Related Questions

SKILL
Given that one side of an equilateral triangle is 16, what is the area of the triangle?

Answers

Answer:

approximately 55.43 or [tex]4\sqrt{192}[/tex]

Step-by-step explanation:

1) draw line down middle of said triangle and split it in half

2) since the area of the triangle is 1/2 b * h we can solve

3) we know that the base is 8 (16 split in 1/2)

4) use the Pythagorean theorem (a^2 +b^2 = c^2) to solve for the height

5) a= 8 b= ? c= 16

6) 16^2=256 8^2= 64  256-64=b^2

7) b=[tex]\sqrt{192}[/tex]

8) [tex]\frac{1}{2} *\sqrt{192} *8= 4\sqrt{192}[/tex] or approximately 55.43

You can check by substituting the numbers back into the Pythagorean theorem and see if they match up

WILL MARK BRANLIEST Give the equation of a line which is perpendicular to the given line. b y=3x+7

Answers

Answer:

y = -1/3 x + 7

Step-by-step explanation:

The constant in the end doesn't matter; what matters is the slope. To find a perpendicular slope, all you have to do is take the reciprocal of the slope and multiply it by -1. As mentioned before, the constant in the end doesn't matter, so the answer could also be y = -1/3x + 10, y = -1/3x -1/2, etc...

Hope this helped.

х2 + 3x = 8
Write the quadratic equation in standard form

Answers

Answer:

[tex]x^{2}[/tex] + 3x - 8 = 0

Step-by-step explanation:

A cube has a volume of 8 cubic inches. What is the length of each edge of the cube?

Answers

Answer:

2in

Step-by-step explanation:

because 2x2x2=8


Dara had to pay $50 in band fees, $25 for the school club fee and $30 for a lab fee how much money does she need to cover her fees

Answers

Answer:

She will need 105$

Step-by-step explanation:

Add 50+25=75 Then add 75+30=105

She has to pay 95 dollars ... $105

A rectangle has an area of 352 square feet. Its widih is ten feet less than twice the length Find the measures of the length and width of the rectangle.​

Answers

Answer:

The Length is 16.

The width is 22.

Step-by-step explanation:

[tex]Area=Width*Length\\352=(2L-10)*(L)\\352=2L^2-10L\\0=2L^2-10L-352\\x=\frac{-b+/-\sqrt{b^2-4ac} }{2a} \\b=-10; a=2; c=-352\\ x=\frac{10+/-\sqrt{100-4(-352)*(2)} }{2*2} \\x=\frac{10+/-\sqrt{100+2816)} }{4}\\x=\frac{10+/-\sqrt{2916)} }{4}\\x=\frac{10+/-54 }{4}\\x=64/4=16[/tex]

PLEASEEEE HELPPPP!!!!!!!

h(x) = 2 - 11
W
ha
- = -5

Answers

Answer:

x= 6

Step-by-step explanation:

h ( x ) = x - 11

h ( 6 ) = 6- 11

h = -5

Simplify i38.
i
−1
−i
1

Answers

The value of ( i )³⁸ will be equal to -1. The correct option is B.

What is an expression?

Numbers (constants), variables, operations, functions, brackets, punctuation, and grouping can all be represented by mathematical symbols, which can also be used to indicate the logical syntax's order of operations and other features.

Given expression ( i )³⁸ is the I value of the complex number. The I value of the complex number is equal to the square root of the negative one. The expression will be solved as below:-

( i )³⁸ = (√-1)³⁸

( i )³⁸ = -1

Therefore, the value of ( i )³⁸ will be equal to -1. The correct option is B.

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Please help me

11-x>17

Answers

Answer:

x < -6

Step-by-step explanation:

Answer:

-7 or x <-6

Step-by-step explanation:

To add to a number that’s in a subtracting equation you must use a negative number because a negative with a subtraction equals adding

PLEASE HELP ASAP!!!!!!! ILL MAKE YOU THE BRAINLEST
Select the three numbers between 2/5 and 250%

0.25
11/4
0.9
2.5%
7/8
78%

Answers

Answer:11/4, 7/8, 78%

Step-by-step explanation:

Answer:

0.9 78% 7/8.I hoped I helped

are the number 25 and 27 twin primes or co prime? why?

Answers

Answer: twin primes

Step-by-step explanation: 27 is 2 more then 25, therefore, they are twin primes.

Jennifer owes her friend $20. What does o mean in this situation?

Answers

We need the rest of the problem a picture or something

Answer:

where is the hole question

Step-by-step explanation:

if a sample of 35 golfers is taken from a population of 72 golfers the sample mean, x, is the mean of how many golfers scores

Answers

Answer: 35

Step-by-step explanation:

The sample mean, denoted by  (pronounced "x bar"), represents the average value of a given variable in a sample. In this case, we are trying to find the sample mean of golfers' scores.

To calculate the sample mean, we need to sum up all the individual scores in the sample and divide by the number of golfers in the sample. Given that we have a sample of 35 golfers from a population of 72 golfers, we can conclude that the sample mean, , represents the mean of the scores of these 35 golfers.

Mathematically, the formula for calculating the sample mean is:  = (x1 + x2 + x3 + ... + xn) / n where x1, x2, x3, ..., xn represent the individual scores, and n represents the sample size. Therefore, the sample mean, , is the average of the scores of the 35 golfers in the sample. To find the exact value, you would need to know the actual scores of each golfer.

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Sally just purchased a beautiful home on a riverbank for what she thought was a very good deal.  She later learned that her house was very susceptible to flood damage during the rainy season.  Which of the following statements best describes the effect the location of Sally’s new home will have on her homeowners insurance premium?

a.

Financial loss due to flood damage is likely.  Her insurance premiums will be higher than homes not on the waterfront.

b.

Since floods are likely, the value of the home decreases significantly, lowering the insurance premium at the same time.

c.

Since floods happen so infrequently, they are not considered a real threat to the value of the home.  Sally’s insurance premium will not be affected.

d.

While extremely annoying, flood damage is usually inexpensive and will not affect the value of the home.  Sally’s insurance premium should not be affected.

Answers

Answer:

A .Financial loss due to flood damage is likely.  Her insurance premiums will be higher than homes not on the waterfront.

Step-by-step explanation:

Got it right on the quiz hope this helps. :)

Statements which best describes, effect the location of Sally’s new home  is, (A) Financial loss due to flood damage is likely.  Her insurance premiums will be higher than homes not on the waterfront.

What is natural disaster insurance?

The natural disaster insurance is the type of insurance in which the insurance company pay the total amount of loan to the beneficiary in case of loss of his property or life in a natural disaster such as earth quack, flood etc.

The face value of natural disaster insurance is depends on following factor:

The face value of natural disaster insurance depends on the location of the house or property.If it is based on the place where the risk of loss due to natural disaster is low, then face value is high and vice versa.Insurance premiums of such places is low, than the place which are at high risk of natural disaster.

Sally just purchased a beautiful home on a riverbank for what she thought was a very good deal.  

She later learned that her house was very susceptible to flood damage during the rainy season.  

In this case, the face value or insurance premiums is high as her house was very susceptible to flood damage during the rainy season.  

Thus, the statements which best describes the effect the location of Sally’s new home will have on her homeowners' insurance premium is, (A) Financial loss due to flood damage is likely.  

Her insurance premiums will be higher than homes not on the waterfront.

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Please help me i cant figure this out!

Answers

Answer:

Step-by-step explanation:

2 a. she has $10 in 5 days.

2 b. she 5 days.

1 a. 1 1/2 divided by 6=0.27 27/100

1 b. 3/4+1/3= 0.58 58/100=29/50

1 c. 1/12

Find the 15th term of the geometric sequence 1, -4, 16, ...

Answers

Answer:

268,435,456

Step-by-step explanation:

Multiply by -4

Find the value of x in the billiard table

Answers

Answer:

x=60

Step-by-step explanation:

It is an equiangulat traingle, so all of the angles will be equal. knowing that the angles of a triangle always add up to 180 degrees, you need to divide 180/3 to find the degrees of each angle.

180/3 = 60

so, x=60

Whitney wants to buy a sweater for $36. If the sales tax rate is 8.25%, what will be
the amount of sales tax on Whitney’s purchase?

A $2.89

B $2.97

C $3.06

D $3.13

Answers

Answer:

B

Step-by-step explanation:

Evaluate
5
9
÷
5
18
jjijijij
kok

Answers

Answer:

i cant even see the words

Step-by-step explanation:

sorry i cant help

If it’s 59 divided by 518 than it’s 0.1138

Thank you guys so much for all the help :)

Answers

No problem bruv!!!!!!

Answer:

29.2

Step-by-step explanation:

This technique is called the Pythagoras Theorem.

a^2+b^2=c^2

15^2+25^2=c^2

225+625=c^2

850=c^2

Take the square root out of both sides.

c= 29.1547595

Round numbers

c= 29.2

Mark me brainliest if you can. Hope this helps.

I need help please!!!!

Answers

Answer:

d

Step-by-step explanation:

The answer is d

Hope this helps

What is 7/8 of 2121?

Answers

Answer:

1855.875

Step-by-step explanation:

All you have to do is multiply them together.

HOPE this helped!!

What are the 2 things we look for when trying to decide if two figures are scaled copies?

Answers

if the angles are the same, and side lengths are equally decreased or increased (depending if you are scaling up or down)

How do you round each number to the place value of the underlined digit?

Answers

Answer:

9. 80, 547.65

10. 135,702.0

Emilio’s family volunteers at the local soup
kitchen every 30 days. Emilio has swimming
lessons every 9 days. He has both activities
this Saturday. When will he have both
activities again on the same day?

Answers

Answer:

Emilio will have both activities again on the same day after 90 days from this Saturday.

Step-by-step explanation:

To solve this question list the multiples of 30 and 9 to find the first common multiple because the two activities will happen again in a number divisible by both 30 and 9.

∵ The multiples of 30 are: 30, 60, 90, 120, ............

∵ The multiples of 9 are: 9, 18, 27, 36, 45, 54, 63, 72, 81, 90, 99, .....

→ The common multiple is 90

∴ The common multiple of 30 and 9 is 90

→ That means the activities will meet again after 90 days from

   this Saturday

Emilio will have both activities again on the same day after 90 days from this Saturday.

The value of m varies inversely as the square of n. When n = 3 m = 6.
What is the positive value of n when m = 13.5?
(I already know C. is wrong)
A. 18
B. 2
C. 9 XXXX
D. 4

Answers

Answer:

B.]2

Step-by-step explanation:

The required positive value of n is 2. Hence, option B is correct.

Important information:

m varies inversely as the square of n.Whem n = 3, then m = 6.Inverse proportion:

It is given that m is inversely proportional to the square of n. So,

[tex]m\propto \dfrac{1}{n^2}[/tex]

[tex]m=\dfrac{k}{n^2}[/tex]           ...(i)

Where, k is the constant of proportionality.

Substitute m = 6 and n = 3 in the above equation.

[tex]6=\dfrac{k}{3^2}[/tex]

[tex]6=\dfrac{k}{9}[/tex]

[tex]6\times 9=k[/tex]

[tex]54=k[/tex]

Substitute this value in (i).

[tex]m=\dfrac{54}{n^2}[/tex]

Substitute m = 13.5 in the above equation.

[tex]13.5=\dfrac{54}{n^2}[/tex]

[tex]n^2=\dfrac{54}{13.5}[/tex]

[tex]n=\pm \sqrt{4}[/tex]

[tex]n=\pm 2[/tex]

Therefore, the required positive value of n is 2. Hence, option B is correct.

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Which situation can be represented by the inequality 155 > 12x + 100 ?
Juanita saves $15 each week. Dan has already saved $100 and saves $12 each week. When
will Juanita have less money than Dan?
O Juanita saves $12 each week. Dan has already saved $100 and saves $15 each week. When
will Juanita have less money than Dan?
Juanita saves $15 each week. Dan has already saved $100 and saves $12 each week. When
will Juanita have more money saved than Dan?
Juanita saves $12 each week. Dan has already saved $100 and saves $15 each week. When
will Juanita have more money saved than Dan?
No

Answers

Answer:

What is the denotative meaning of “electrified fence”?

✔ a fence with an electric current

What is the connotative meaning of “electrified fence” in the passage?

✔ something dangerous and painful

What does the use of this phrase reveal about how the author views communism?

✔ She believes that communism is oppressive.

Step-by-step explanation:

trast me that the right answer


Alice made the conjecture 5x = 30 and x = 5. Which of the following is true to her conjecture?
O True, x = 5
O True, x = -6
O False x = -5
O False, x = 6


Answers

Answer:

False, x=6

Step-by-step explanation:

5x=30

Divide 5 on both sides

5/5 leaves x

30/5=6

Bring down x

x=6

help this is overdue

35 <7(2−b) or 13(15b−12)≥21

Answers

35 < 7 ( 2-b ) or 13 ( 15b-12)>= 21

35 < 14 - 7b or 195 b - 156 >= 2

35-14<-7b or 195b >= 2 + 156

21 < -7b or 195 b >= 158

b < 21/-7 or b>= 158/195

b < -3 or b >= 158/195

The simplification form of the inequality 35 <7(2−b) or 13(15b−12)≥21 is b < -3 or b  ≥  158/195.

What is inequality?

It is defined as the expression in mathematics in which both sides are not equal they have mathematical signs either less than or greater than known as inequality.

It is given that:

The inequality is:

35 < 7(2 − b) or 13(15b − 12) ≥ 21

After simplification:

35 < 14 - 7b or 195 b - 156 ≥  2 (using distributive property)

35-14<-7b or 195b ≥  2 + 156

21 < -7b or 195 b ≥  158

b < 21/-7 or b ≥  158/195 (division property of equality)

b < -3 or b  ≥  158/195

Thus, the simplification form of the inequality 35 <7(2−b) or 13(15b−12)≥21 is b < -3 or b  ≥  158/195.

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what is 2x1,000 plz help

Answers

Answer:

2,000

Step-by-step explanation:

Count 1,000 twice. 2 x 1,000 = 2,000. Have a nice day!

Answer:

2000

Step-by-step explanation:

Ignore the 0s since anything times 0 is 0. Multiply 1 by 2. Put the zeroes in the answer and it's 2000

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