6 Over time it has been accepted that the mean retirement age for professional baseball players is 29.5 years old.
Imran claims that the mean retirement age is no longer 29.5 years old.
He takes a random sample of 5 recently retired professional baseball players and records their retirement ages, \(x\). The results are
$$\sum x = 152.1 \quad \text { and } \quad \sum ( x - \bar { x } ) ^ { 2 } = 7.81$$
6
- State an assumption that you should make about the distribution of the retirement ages to investigate Imran's claim.
6
- Investigate Imran's claim, using the 10\% level of significance.