CAIE Further Paper 4 2023 November — Question 5

Exam BoardCAIE
ModuleFurther Paper 4 (Further Paper 4)
Year2023
SessionNovember
TopicWilcoxon tests

5 A company is deciding which of two machines, \(X\) and \(Y\), can make a certain type of electrical component more quickly. The times taken, in minutes, to make one component of this type are recorded for a random sample of 8 components made by machine \(X\) and a random sample of 9 components made by machine \(Y\). These times are as follows.
Machine \(X\)4.04.64.74.85.05.25.65.8
Machine \(Y\)4.54.95.15.35.45.75.96.36.4
The manager claims that on average the time taken by machine \(X\) to make one component is less than that taken by machine \(Y\).
  1. Carry out a Wilcoxon rank-sum test at the \(5 \%\) significance level to test whether the manager's claim is supported by the data.
  2. Assuming that the times taken to produce the components by the two machines are normally distributed with equal variances, carry out a \(t\)-test at the \(5 \%\) significance level to test whether the manager's claim is supported by the data.
    \section*{Question 5(c) is printed on the next page.}
  3. In general, would you expect the conclusions from the tests in parts (a) and (b) to be the same? Give a reason for your answer.
    If you use the following page to complete the answer to any question, the question number must be clearly shown.