Edexcel S4 2009 June — Question 3

Exam BoardEdexcel
ModuleS4 (Statistics 4)
Year2009
SessionJune
TopicHypothesis test of binomial distributions
TypeTwo-tailed test critical region

  1. Define, in terms of \(\mathrm { H } _ { 0 }\) and/or \(\mathrm { H } _ { 1 }\),
    1. the size of a hypothesis test,
    2. the power of a hypothesis test.
    The probability of getting a head when a coin is tossed is denoted by \(p\).
    This coin is tossed 12 times in order to test the hypotheses \(\mathrm { H } _ { 0 } : p = 0.5\) against \(\mathrm { H } _ { 1 } : p \neq 0.5\), using a 5\% level of significance.
  2. Find the largest critical region for this test, such that the probability in each tail is less than 2.5\%.
  3. Given that \(p = 0.4\)
    1. find the probability of a type II error when using this test,
    2. find the power of this test.
  4. Suggest two ways in which the power of the test can be increased.