2 The length, in minutes, of mathematics lectures at a certain college has mean \(\mu\) and standard deviation 8.3.
- The total length of a random sample of 85 lectures was 4590 minutes.
Calculate a 95\% confidence interval for \(\mu\).
The length, in minutes, of history lectures at the college has mean \(m\) and standard deviation \(s\). - Using a random sample of 100 history lectures, a 95\% confidence interval for \(m\) was found to have width 2.8 minutes.
Find the value of \(s\).