2016, Question 4 · 4 points
Model rocket igniter failure testing
Find the chance 30 igniters in a row work at a 15 percent failure rate, find the chance the first failure comes on the next one or two given that streak, and judge whether the streak suggests a lower failure rate.
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.
Not in the current course. Part (b) asks when the first failure occurs, which is the geometric distribution setting the current course no longer includes.
Lessons this question draws on
1 Read the question
The question is College Board's, from the 2016 exam. It starts on page 9 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 April 24, 2025.
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 11) 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.