CAIE S2 2013 June — Question 7

Exam BoardCAIE
ModuleS2 (Statistics 2)
Year2013
SessionJune
TopicHypothesis test of binomial distributions
TypeCalculate Type I error probability

7 Leila suspects that a particular six-sided die is biased so that the probability, \(p\), that it will show a six is greater than \(\frac { 1 } { 6 }\). She tests the die by throwing it 5 times. If it shows a six on 3 or more throws she will conclude that it is biased.
  1. State what is meant by a Type I error in this situation and calculate the probability of a Type I error.
  2. Assuming that the value of \(p\) is actually \(\frac { 2 } { 3 }\), calculate the probability of a Type II error. Leila now throws the die 80 times and it shows a six on 50 throws.
  3. Calculate an approximate \(96 \%\) confidence interval for \(p\).