I need help

Suppose that a random sample of sixteen recently sold houses in a certain city has a mean sales price of $280,000, with a standard deviation of $15,000. Under the assumption that house prices are normally distributed, find a 90% confidence interval for the mean sales price of all houses in this community. Then find the lower limit and upper limit of the 90% confidence interval. Carry your intermediate computations to at least three decimal places. Round your answers to the nearest whole number. (If necessary, consult a list of formulas.) Lower limit: $[I] Upper limit: $D