OCR S1 2009 June — Question 9

Exam BoardOCR
ModuleS1 (Statistics 1)
Year2009
SessionJune
TopicGeometric Distribution
TypeFind minimum n for P(X ≤ n) > threshold

9 Repeated independent trials of a certain experiment are carried out. On each trial the probability of success is 0.12 .
  1. Find the smallest value of \(n\) such that the probability of at least one success in \(n\) trials is more than 0.95.
  2. Find the probability that the 3rd success occurs on the 7th trial.