The free response questions for the AP Statistics exam are sometimes hard to predict. What trends do exist?
Here is A graph relating AP Free response question Number vs. Chapter in the 5th Edition of The Practice of Statistics.
1: Exploring Data (single variable, quantitative)
2: Modeling Distributions of Data (z-scores, percentiles, normal model)
3: Describing Relationships
4: Collecting Data
5: Probability, the basics
6: Random Variables, the binomial and geometric distribution.
7: Sampling Distributions
8: Inference: Confidence Intervals, 1 variable.
9: Significance Tests, 1 variable.
10: Inference for two groups
11: Inference for categorical data
12: Inference for regression
Here’s a graph of the relationship. Here are a few trends I observe:
- Question 1 tends to be exploratory data analysis OR an easier test about inference.
- Question 2 seems to feature probability OR sampling/ experimental design
- Question 3 seems to feature probability OR sampling/ experimental design
- Question 4 seems to feature an inference procedure often, but not always
- Question 5 seems to feature an inference procedure often, but not always.
- Question 6 always is a mixed bag, bot often involves some reasoning regarding inference.
- “Probability, served three ways:” Probability questions are often, but not always, three-parters that take a single scenario and then “serve up” questions involving three different techniques in probability.
- Two sample t vs Matched Pairs t questions are common.
- Inference for regression, when addressed, is done pretty lightly, and often in question 6. There are often many other parts to question 6 that are not about inference for regression.
Now, if you can only figure out if there is a pattern to what type of inference there will be from year to year!