AP Stats Stats: Key Skills Assessed 3

Question 1

A chi-square goodness-of-fit test is used to determine whether:

Accepted Answer

Observed categorical frequencies match expected frequencies

Answer

The chi-square goodness-of-fit test compares observed counts to expected counts for one categorical variable.

Question 2

In a simple linear regression model ŷ = a + bx, the slope b represents:

Accepted Answer

The predicted change in y for a one-unit increase in x

Answer

The slope b is the predicted change in the response variable for each one-unit increase in the explanatory variable.

Question 3

If a distribution has a mean of 80 and a standard deviation of 10, what percentage of data falls between 60 and 100 according to the Empirical Rule?

Accepted Answer

95%

Answer

60 and 100 are each 2 standard deviations from the mean (80 ± 20), so approximately 95% of data falls in this range.

Question 4

A probability sample in which every member of the population has an equal chance of being selected is called a:

Accepted Answer

Simple random sample

Answer

A simple random sample (SRS) gives every individual an equal probability of selection.

Question 5

When the p-value of a hypothesis test is less than the significance level α, the correct conclusion is:

Accepted Answer

Reject the null hypothesis

Answer

A p-value below α means the data provides sufficient evidence to reject the null hypothesis.

AP Practice Test