Question 3 (4 marks)

Part a)

The mean of a sample of 25 was calculated as mean of 500. The sample was randomly drawn from a population whose standard deviation is 15. Estimate the population means with 99% confidence.

Part b)

A random sample of 5 observations was drawn from a normal population. The sample same and standard deviation are X =175 and s=30. Estimate the population mean with 90% confidence.