3 Jagdeesh measured the lengths, \(x\) minutes, of 60 randomly chosen lectures. His results are summarised below.
$$n = 60 \quad \Sigma x = 3420 \quad \Sigma x ^ { 2 } = 195200$$
- Calculate unbiased estimates of the population mean and variance.
- Calculate a \(98 \%\) confidence interval for the population mean.