I'm having trouble with this question. A sample of 1,000 U. households is taken and the average amount of newspaper garbage or recycling is found to...

I'm having trouble with this question.

A sample of 1,000 U.S. households is taken and the average amount of newspaper garbage or recycling is found to be 27.8 pounds with a standard deviation of 2 pounds. Estimate, with 90% confidence, the mean amount of newspaper garbage or recycling for the American households.

Keep intermediate steps to four decimals when possible & enter your answer to two decimals.