Exhibit 9-3

Multiple Choice

Exhibit 9-3.The Boston public school district has had difficulty maintaining on-time bus service for its students ("A Year Later,School Buses Still Late," Boston Globe,October 5,2011) .Suppose the district develops a new bus schedule to help combat chronic lateness on a particularly woeful route.Historically,the bus service on the route has been,on average,12 minutes late.After the schedule adjustment,the first 36 runs were an average of 8 minutes late.As a result,the Boston public school district claimed that the schedule adjustment was an improvement-students were not as late.Assume a population standard deviation for bus arrival time of 12 minutes. Refer to Exhibit 9-3.At the 5% significance level,does the evidence support the Boston public school district's claim?

A) No,since the p-value is less than α.
B) Yes,since the p-value is less than α.
C) No,since the value of the test statistic is greater than the critical value.
D) Yes,since the value of the test statistic is greater than the critical value.