The Wind Mountain archaeological site is located in southwestern New Mexico. Wind Mountain was home to an ancient culture of prehistoric Native Americans called Anasazi. A random sample of excavations at Wind Mountain gave the following depths (in centimeters) from present-day surface grade to the location of significant archaeological artifacts.

85 45 120 80 75 55 65 60 65 95 90 70 75 65 68

(a) Use a calculator with mean and sample standard deviation keys to find the sample meanxand sample standard deviations. (Round your answers to one decimal place.)

(b) Compute a99%confidence interval for the mean depthat which archaeological artifacts from the Wind Mountain excavation site can be found. (Round your answers to one decimal place.)