4 A speed camera was used to measure the speed, \(V\) mph, of John's serves during a tennis singles championship.
For 10 randomly selected serves,
$$\sum v = 1179 \quad \text { and } \quad \sum ( v - \bar { v } ) ^ { 2 } = 1014.9$$
where \(\bar { v }\) is the sample mean.
- Construct a \(99 \%\) confidence interval for the mean speed of John's serves at this tennis championship, stating any assumption that you make.
(7 marks) - Hence comment on John's claim that, at this championship, he consistently served at speeds in excess of 130 mph .
(1 mark)