4 A set of observations of a random variable \(W\) can be summarised as follows:
$$n = 14 , \quad \Sigma w = 100.8 , \quad \Sigma w ^ { 2 } = 938.70 .$$
- Calculate an unbiased estimate of the variance of \(W\).
- The mean of 70 observations of \(W\) is denoted by \(\bar { W }\). State the approximate distribution of \(\bar { W }\), including unbiased estimate(s) of any parameter(s).