A sample of 36 vacation homes built during the past 2 years in a coastal resort region

Question:

A sample of 36 vacation homes built during the past 2 years in a coastal resort region gave a mean construction cost of $159,000 with a population standard deviation of $27,000.
a. What is the point estimate of the corresponding population mean?
b. Make a 99% confidence interval for the mean construction cost for all vacation homes built in this region during the past 2 years. What is the margin of error here?