Up until recently, your potato chip factory in Los Angeles was producing chips an average thickness of 1.35 millimeters (1.35mm). Recently, new manufacturing equipment was introduced and your customers have suddenly started reporting that the potato chips have gotten thinner. Naturally, you are worried about this, so you arrange to have a random sample of 16 chips taken from the population of all chips produced yesterday. The random samples shows an average thickness of 1.25 mm and a standard deviation of .12mm.

Assuming that the thickness of the chips is Normally distributed, construct a 90% confidence interval for the mean thickness of all chips produced yesterday based upon the sample of size 16.