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Questions 21 and 22 are related 21 Consider the mean cost of getting a four-year

ID: 3047775 • Letter: Q

Question

Questions 21 and 22 are related

21 Consider the mean cost of getting a four-year college degree. The middle interval which captures 95% of mean costs from samples of 36 graduates is ($48,750, 53,650). What is the population mean cost of getting a college degree?

a $52,100

b $51,200

c $50,500

d $49,900

22 in the previous question, suppose we want to build a middle interval which captures 95% of the sample means within ±$1,000 from the population mean. What is the minimum sample size that would yield such an interval?

a 217

b 207

c 197

d 187

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27 In the previous question, what fraction of sample proportions from samples of size 400 fall within ±0.03 from the population proportion?

a 0.8904

b 0.8384

c 0.8064

d 0.7888

Explanation / Answer

Solution21:

sample mean is best estimator of population mean

we are given 95% CI estimates

samplemean-MOE=48,750

sample mean+MOE=53,650

add 2 eq

2(samplemean)=48,750+53,650

samplemean=102400/2

=51200

OPTION B