The U.S. Army commissioned a study to assess how deeply a bullet penetrates ceramic body armor ("Testing Body Armor Materials for Use by the U.S. Army- Phase III," 2012). In the standard test, a cylindrical clay model is layered under the armor vest. A projectile is then fired, causing an indentation in the clay. The deepest impression in the clay is measured as an indication of survivability of someone wearing the armor. Here is data from one testing organization under particular experimental conditions; measurements (in mm) were made using a manually controlled digital caliper:

a. Construct a boxplot of the data and comment on interesting features.
b. Construct a normal probability plot. Is it plausible that impression depth is normally distributed? Is a normal distribution assumption needed in order to calculate a confidence interval or bound for the true average depth µ using the foregoing data? Explain.
c. Use the accompanying Minitab output as a basis for calculating and interpreting an upper confidence bound for µ with a confidence level of 99%.

6687955927150 5790123355671 2223333333334 54777558051480 7901233556795 22233333333335 97656436640083 46901233456788 22233333333334 04144116640676 46901233456684 22233333333334 61000095240401 36901223456682 22233333333334 48390965128250 25891123455672 22223333333334 Variable Count Mean SE Mean stDew Depth Q1 30.400 33.500 36.000 5.600 83 33.370 0.578 5.268 Median Q3 IQR