CAIE S1 2024 November — Question 1

Exam BoardCAIE
ModuleS1 (Statistics 1)
Year2024
SessionNovember
TopicConditional Probability
TypeBasic two-way table probability

1 At a college, the students choose exactly one of tennis, hockey or netball to play. The table shows the numbers of students in Year 1 and Year 2 at the college playing each of these sports.
TennisHockeyNetball
Year 1162212
Year 2241828
One student is chosen at random from the 120 students. Events \(X\) and \(N\) are defined as follows:
\(X\) : the student is in Year 1
\(N\) : the student plays netball.
  1. Find \(\mathrm { P } ( X \mid N )\).
  2. Find \(\mathrm { P } ( N \mid X )\).
  3. Determine whether or not \(X\) and \(N\) are independent events.
    One of the students who plays netball takes 8 shots at goal. On each shot, the probability that she will succeed is 0.15 , independently of all other shots.
  4. Find the probability that she succeeds on fewer than 3 of these shots.