Refer to Applied Example 9.20, “Ceramic Floor Tile,” on page 461. First you need to complete a preliminary investigation of the 26 randomly selected surface heights:
a. Present and describe the sample of surface heights using a histogram, the mean, and the standard deviation.
b. Check the surface heights for a normal distribution. State what you believe to be the case based on the results found in part a. Further, find additional statistical evidence. Very precisely state your conclusion regarding normality for the distribution of this variable. Statistical testing of the manufacturing process:
c. Is there statistical evidence that the process used to manufacture these floor tiles has produced a textured surface that has a mean surface height no greater than 0.025 inch? State the p-value.
d. Complete the hypothesis test at the 0.01 level of significance; be sure to state your decision and conclusion.