AP Stats Stats: Evaluation Overview 2

Question 1

A researcher wants to test whether a new drug reduces blood pressure. Which type of study provides the strongest evidence of causation?

Accepted Answer

Randomized controlled experiment

Answer

Observational cohort study

Answer

Stratified survey

Answer

Case-control study

Question 2

In hypothesis testing, the p-value represents:

Accepted Answer

The probability of observing results at least as extreme as the sample, assuming H₀ is true

Answer

The probability the null hypothesis is true

Answer

The probability the alternative hypothesis is true

Answer

The significance level chosen by the researcher

Question 3

A 95% confidence interval for a population mean is (12.4, 18.6). Which interpretation is correct?

Accepted Answer

If we repeated sampling many times, about 95% of such intervals would contain the true mean

Answer

There is a 95% chance the true mean falls in this interval

Answer

95% of sample means fall between 12.4 and 18.6

Answer

The sample mean has a 95% probability of being correct

Question 4

Which of the following is an example of a Type I error?

Accepted Answer

Rejecting a true null hypothesis

Answer

Failing to reject a false null hypothesis

Answer

Setting alpha too small

Answer

Using a one-tailed test instead of two-tailed

Question 5

A scatterplot shows a strong negative linear association between two variables. The correlation coefficient r is most likely:

Accepted Answer

-0.92

Answer

0.85

Answer

0.05

Answer

-0.10

Question 6

Which condition must be checked when performing a chi-square test for independence?

Accepted Answer

All expected cell counts are at least 5

Answer

All observed cell counts are equal

Answer

The sample size is less than 30

Answer

The variables are normally distributed

Question 7

A school surveys a random sample of 200 students and finds 60% prefer online learning. The margin of error at 95% confidence is ±6.8%. What does this margin of error indicate?

Accepted Answer

We are 95% confident the population proportion is within 6.8% of 60%

Answer

60% of the population prefers online learning

Answer

The true proportion is exactly between 53.2% and 66.8%

Answer

6.8% of students were incorrectly surveyed