3 Alan's journey time to work can be modelled by a normal distribution with standard deviation 6 minutes.
Alan measures the journey time to work for a random sample of 5 journeys. The mean of the 5 journey times is 36 minutes.
3
- Construct a 95\% confidence interval for Alan's mean journey time to work, giving your values to one decimal place.
3 - Alan claims that his mean journey time to work is 30 minutes.
State, with a reason, whether or not the confidence interval found in part (a) supports Alan's claim.
3 - Suppose that the standard deviation is not known but a sample standard deviation is found from Alan's sample and calculated to be 6
Explain how the working in part (a) would change.