A simple random sample of 12 Droids being sold over the Internet had the following prices, in dollars. 287, 311, 262, 392, 313, 341, 336, 316, 286,...

A simple random sample of 12 Droids being sold over the Internet had the following prices, in dollars.  287, 311, 262, 392, 313, 341, 336, 316, 286, 299, 291. 

Assume that it is reasonable to believe that the population is approximately normal and the population standard deviation is 54.  What is the upper bound of the 95% confidence interval for the mean price for all phone types?