1 Each of a random sample of 80 adults gave an estimate, \(h\) metres, of the height of a particular building. The results were summarised as follows.
$$n = 80 \quad \Sigma h = 2048 \quad \Sigma h ^ { 2 } = 52760$$
- Calculate unbiased estimates of the population mean and variance.
- Using this sample, the upper boundary of an \(\alpha \%\) confidence interval for the population mean is 26.0 .
Find the value of \(\alpha\).