1999, Question 3 · 4 points
Apples and dental cavities
Explain why a study of apple eaters' cavities is observational, describe confounding with an example, and judge whether a significant difference shows that apples cause fewer cavities.
This exam had six free-response questions, each scored from 0 to 4. Its Question 6, the Investigative Task, is no longer part of the exam. The current exam has 4 free-response questions in 90 minutes. The skills these questions practice still count.
Lessons this question draws on
1 Read the question
The question is College Board's, from the 1999 exam. It starts on page 7 of the PDF. College Board no longer posts this exam, so it opens from the copy of College Board's PDF that the Internet Archive saved on February 19, 2026.
2 Write your answer
Answer each part the way you would on the exam, in full sentences, with your work shown. Your writing saves as you type.
3 Score it
Score your answer against College Board's scoring guidelines, one point at a time. Give yourself a point only when your answer says what the guideline asks for.
Scoring guidelines (PDF, page 7)
Question, scoring guidelines and Chief Reader report: College Board, from the Internet Archive. The title and summary are ours.