Reconsider the previous exercise.
a. Th e data file CarCrashDummiesLog contains the same data but with the response variable being the logarithm (base 10) of the original head injury measurements. Reexamine the distributions of these (transformed) measurements by the number of doors. Do the validity conditions appear to be satisfied now? Explain.
b. Determine the ANOVA table and interpret the results. Do the data provide strong evidence that head injury measurements diff er based on the number of doors on the vehicle? Explain.
c. Produce confidence intervals to determine which groups diff er significantly from which others. Summarize your findings.

Data from previous exercise

The data file CarCrashDummies contains data on automobile crash test results. The explanatory variable is the number of doors on the vehicle, and the response variable is a measurement of the extent of injury on the dummy’s head.