4 The heights of eleven randomly selected primary school children are measured. The results, in metres, are
| Girls | 1.48 | 1.31 | 1.63 | 1.38 | 1.56 | 1.57 |
| Boys | 1.44 | 1.35 | 1.32 | 1.28 | 1.27 | |
- Use a Wilcoxon rank-sum test, at the \(1 \%\) significance level, to test whether primary school girls are taller than primary school boys.
- It is decided to repeat the test, using larger random samples. The heights of twenty girls and eighteen boys are measured. Find the greatest value of the test statistic \(W\) which will result in the conclusion that there is evidence, at the \(1 \%\) level of significance, that primary school girls are taller than primary school boys.