Suppose that scores for men on an aptitude test have greater variability than scores for women on the same test.In other words,the population standard deviation is greater for the population of men than for the population of women.Based on a sample of size 50,a 95% confidence interval for the mean score,μ,of all women has a margin of error of 2.2.Which of the following confidence intervals will have a smaller margin of error?
I.A 99% confidence interval for the mean score of women.Sample size = 50
II.A 95% confidence interval for the mean score of women.Sample size = 100
III.A 95% confidence interval for the mean score of men.Sample size = 50

Question

Suppose that scores for men on an aptitude test have greater variability than scores for women on the same test.In other words,the population standard deviation is greater for the population of men than for the population of women.Based on a sample of size 50,a 95% confidence interval for the mean score,μ,of all women has a margin of error of 2.2.Which of the following confidence intervals will have a smaller margin of error?
 I.A 99% confidence interval for the mean score of women.Sample size = 50
II.A 95% confidence interval for the mean score of women.Sample size = 100
III.A 95% confidence interval for the mean score of men.Sample size = 50

Quizplus · Accepted Answer

Increasing the sample size to 100 (as in II) reduces the margin of error, while increasing the confidence level to 99% (as in I) increases it. The variability of men's scores (as in III) does not affect the margin of error for women's scores.

Suppose That Scores for Men on an Aptitude Test Have