A school administrator claimed that the average time spent on a school bus by those students in his school district who rode school buses was 35 minutes. A random sample of 20 students who did ride the school buses yielded an average of 42 minutes riding time with a standard deviation of 6.2 minutes. Does this sample of size 20 contain sufficient evidence to indicate that the mean riding time is greater than 35 minutes at the 5% level of significance? Solution: Step 1 Ho : ( >= (greater than or equal to) 35 vs. H1 : A