An investigator wishes to determine whether alcohol consumption causes deterioration in the performance of automobile drivers. Before the driving test, subjects drank a glass of orange juice which, in the case of the treatment group, is laced with three ounces of vodka. Performance is measured by the number of errors made on a driving simulator. There were one hundred and sixty six volunteer subjects which were randomly assigned, in equal numbers, to the two groups. For subjects in the treatment group, the mean number of errors ( x1 ) equals 24 and the standard deviation ( s1 ) equals 17.5. For subjects in the control group, the mean number of errors ( x2 ) equals 20, and the standard deviation ( s2 ) equals 10.85. Test the claim that alcohol consumption causes deterioration in the performance of automobile drivers.