Statistics Hypothesis Testing & Inference 2

Question 1

A 95% confidence interval for a population mean is (42, 58). What does this mean?

Accepted Answer

We are 95% confident the true population mean falls between 42 and 58

Answer

A 95% CI means that 95% of intervals constructed this way from repeated samples would contain the true parameter.

Question 2

The chi-square test of independence is used to evaluate which type of claim?

Accepted Answer

Whether two categorical variables are associated

Answer

The chi-square test of independence tests whether there is a statistically significant association between two categorical variables.

Question 3

What happens to the width of a confidence interval as sample size increases?

Accepted Answer

It decreases

Answer

Larger samples reduce the standard error, which narrows the confidence interval.

Question 4

Which non-parametric test is the alternative to the independent-samples t-test?

Accepted Answer

Mann-Whitney U test

Answer

The Mann-Whitney U test compares two independent groups using ranked data without assuming normality.

Question 5

What is the purpose of a paired t-test?

Accepted Answer

To compare means from two related or matched samples

Answer

The paired t-test accounts for the correlation between two related measurements, such as before-and-after data.

Statistics Practice Test