A local health care company has asked you to to determine the average weekly costs of elderly day-care. They provided you with a random sample of 10 facilities. This shows a mean of $250 per week, with a standard deviation of $25. Note that the population parameters are unknown.
a) What is the point estimate for the population mean?
b) What is the 90% confidence interval for the population mean?
As you are presenting your results to the company, you realise that they have no idea what a confidence interval is.
c) Explain how the confidence interval should be interpreted, using your answer (b) as point of departure.