Statistics Hypothesis Testing & Inference

Question 1

What does the null hypothesis (H₀) typically represent in a statistical test?

Accepted Answer

No effect or no difference exists in the population

Answer

The null hypothesis is the default claim of no effect, no difference, or no relationship.

Question 2

What is a Type I error in hypothesis testing?

Accepted Answer

Rejecting a true null hypothesis

Answer

A Type I error (false positive) occurs when we reject a null hypothesis that is actually true.

Question 3

If a p-value is 0.03 and the significance level α is 0.05, what conclusion is drawn?

Accepted Answer

Reject the null hypothesis

Answer

Since p = 0.03 < α = 0.05, there is sufficient evidence to reject the null hypothesis.

Question 4

Which test is appropriate for comparing the means of two independent groups?

Accepted Answer

Two-sample t-test

Answer

The two-sample (independent samples) t-test compares means from two separate, unrelated groups.

Question 5

What does statistical power represent?

Accepted Answer

The probability of correctly rejecting a false null hypothesis

Answer

Power is the probability of detecting a true effect (1 − β, where β is the Type II error rate).

Statistics Practice Test