9231 P41 - Jun 2024 - Q3 - 8 marks
6662
A factory produces metal discs. The manager claims that the diameters of these discs have a median of 22.0 mm . The diameters, in mm , of a random sample of 12 discs produced by this factory are as follows.
| 22.4 | 20.9 | 22.8 | 21.5 | 23.2 | 22.9 | 23.9 | 21.7 | 19.8 | 23.6 | 22.6 | 23.0 |
(a) Carry out a Wilcoxon signed-rank test, at the \(10 \%\) significance level, to test whether there is any evidence against the manager's claim.
(b) State an assumption that is necessary for this test to be valid.
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