OCR MEI S1 2012 June — Question 4

Exam BoardOCR MEI
ModuleS1 (Statistics 1)
Year2012
SessionJune
TopicGeometric Distribution
TypeFirst success on specific trial

4 It is known that \(8 \%\) of the population of a large city use a particular web browser. A researcher wishes to interview some people from the city who use this browser. He selects people at random, one at a time.
  1. Find the probability that the first person that he finds who uses this browser is
    (A) the third person selected,
    (B) the second or third person selected.
  2. Find the probability that at least one of the first 20 people selected uses this browser.