5 Of two brands of lawnmower, \(A\) and \(B\), brand \(A\) was claimed to take less time, on average, than brand \(B\) to mow similar stretches of lawn. In order to test this claim, 9 randomly selected gardeners were each given the task of mowing two regions of lawn, one with each brand of mower. All the regions had the same size and shape and had grass of the same height. The times taken, in seconds, are given in the table.

1. Test the claim using a paired-sample \(t\)-test at the \(5 \%\) significance level. State a distributional assumption required for the test to be valid.
2. Give a reason why a paired-sample \(t\)-test should be used, rather than a 2 -sample \(t\)-test, in this case.