Question: A study was conducted by the State Transportation Department to determine whether a weigh-in-motion (WIM) scale could be used in place of the static scale currently used at port-of-entry(POE) locations across the state. The WIM scale weighs trucks as they drive over a scale, rather than making them stop at a POE to be weighed. It is thought that the mean speed of trucks crossing the WIM scale would be less that the posted speed limit of 65 miles per hour. Using the file Trucks on the CD-ROM:

a. What conclusion can be reached concerning the preconception about the average speed at a significance level of .1? (2 points)

b. A published report indicates that the WIM scale average truck length on the state highway exceeds 60 feet. Based on the sample data, can this claim be supported or refuted at a significance level of .05? (2 points)

c. Create a new variable that represents the difference between the WIM gross weight and the POE gross weight. It is thought that if the WIM scale were effective that the average difference would be 0. Based on the sample data, what can be concluded at a significance level of .05? (3 points)