AP Stats Hypothesis Testing 3

Question 1

A school claims its average SAT score is 1100. A sample of 36 students yields x̄ = 1080 and s = 90. What is the test statistic for a one-sample t-test?

Accepted Answer

t = −1.33

Answer

t = (1080 − 1100) / (90 / √36) = −20 / 15 ≈ −1.33.

Question 2

Which statement about p-values is correct?

Accepted Answer

A p-value is the probability of obtaining results as extreme or more extreme, assuming H₀ is true.

Answer

The p-value measures how likely the observed data (or more extreme) would be if H₀ were true, not the probability that H₀ is true.

Question 3

For a chi-square goodness-of-fit test, the degrees of freedom equal:

Accepted Answer

Number of categories − 1

Answer

Degrees of freedom for a goodness-of-fit test = k − 1, where k is the number of categories.

Question 4

A significance test yields z = 2.45 for a right-tailed test. The p-value is approximately:

Accepted Answer

0.007

Answer

For z = 2.45 in a right-tailed test, p = P(Z > 2.45) ≈ 0.007.

Question 5

Which condition is necessary for a two-sample t-test to be valid?

Accepted Answer

The two samples must be independent of each other.

Answer

Independence between the two groups is a required condition; normality is only needed if sample sizes are small.

AP Practice Test

AP Practice Test

AP Stats Hypothesis Testing 3