OCR S4 2010 June — Question 5

Exam BoardOCR
ModuleS4 (Statistics 4)
Year2010
SessionJune
TopicWilcoxon tests

5 In order to test whether the median salary of employees in a certain industry who had worked for three years was \(\pounds 19500\), the salaries \(x\), in thousands of pounds, of 50 randomly chosen employees were obtained.
  1. The values \(| x - 19.5 |\) were calculated and ranked. No two values of \(x\) were identical and none was equal to 19.5 . The sum of the ranks corresponding to positive values of \(( x - 19.5 )\) was 867. Stating a required assumption, carry out a suitable test at the \(5 \%\) significance level.
  2. If the assumption you stated in part (i) does not hold, what test could have been used?