Edexcel S4 2008 June — Question 6

Exam BoardEdexcel
ModuleS4 (Statistics 4)
Year2008
SessionJune
TopicHypothesis test of binomial distributions
TypeCalculate Type I error probability

  1. A drug is claimed to produce a cure to a certain disease in \(35 \%\) of people who have the disease. To test this claim a sample of 20 people having this disease is chosen at random and given the drug. If the number of people cured is between 4 and 10 inclusive the claim will be accepted. Otherwise the claim will not be accepted.
    1. Write down suitable hypotheses to carry out this test.
    2. Find the probability of making a Type I error.
    The table below gives the value of the probability of the Type II error, to 4 decimal places, for different values of \(p\) where \(p\) is the probability of the drug curing a person with the disease.
    P (cure)0.20.30.40.5
    P (Type II error)0.5880\(r\)0.8565\(s\)
  2. Calculate the value of \(r\) and the value of \(s\).
  3. Calculate the power of the test for \(p = 0.2\) and \(p = 0.4\)
  4. Comment, giving your reasons, on the suitability of this test procedure.