Question 1

A technician wishes to estimate the average re-start time among 180 machines in a factory after complete shutdown. A random sample of 15 machine was selected and their restart times were recorded. The sample mean and the standard deviation were found to be 3.0 seconds and 0.4 seconds, respectively.

1.Estimate the population mean.

2.Place a bound on the error of estimation

3.Calculate the 95% confidence interval for the estimated population mean.

Question 2

Explain why sampling techniques are necessary for a country's national statistics office?

Question 3

As a statistician explain how are you going to decide on the type of sampling to use to carry out research.