2011, Question 6 · 4 points · about 25 minutes
How many students really know the answer?
Build and interpret a 99 percent interval for a proportion, fill in a tree diagram for knowing versus guessing, write the chance of a correct answer in terms of k, and convert the interval into one for k.
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.
1 Read the question
The question is College Board's, from the 2011 exam. It starts on page 11 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 November 25, 2025.
Open Question 6 (PDF, page 11)
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 17) What the exam readers saw (Student Performance Q&A)
Question, scoring guidelines and Chief Reader report: College Board, from the Internet Archive. The title, summary are ours.