AP Stats Hypothesis Testing 2

Question 1

A researcher conducts a two-sided t-test and obtains a p-value of 0.03. Which conclusion is most appropriate at the α = 0.05 level?

Accepted Answer

Reject H₀; the results are statistically significant.

Answer

Since 0.03 < 0.05, we reject H₀ and conclude the results are statistically significant at the 5% level.

Question 2

In a hypothesis test, a Type II error occurs when you:

Accepted Answer

Fail to reject a false null hypothesis.

Answer

A Type II error (β) is failing to reject H₀ when H₀ is actually false — missing a real effect.

Question 3

The power of a hypothesis test is best described as:

Accepted Answer

1 minus the probability of a Type II error.

Answer

Power = 1 − β, the probability of correctly rejecting a false null hypothesis.

Question 4

Which of the following actions will INCREASE the power of a hypothesis test, all else equal?

Accepted Answer

Increasing the sample size.

Answer

Larger samples reduce variability, making it easier to detect a true difference and thus increasing power.

Question 5

A one-proportion z-test requires which condition regarding expected counts?

Accepted Answer

np ≥ 5 and n(1−p) ≥ 5 using the null proportion.

Answer

For a z-test on proportions, both np₀ and n(1−p₀) must be at least 10 (some curricula use 5) to ensure the sampling distribution is approximately normal.

AP Practice Test

AP Practice Test

AP Stats Hypothesis Testing 2