Safety researchers in a government agency believe that too much variability in the speeds of vehicles on urban sections of interstate highways can contribute to accidents by causing a greater level of interaction between vehicles traveling in the same direction. They believe that a standard deviation in excess of 5 mph is undesirable. Observing a random sample of vehicles on an urban portion of the interstate highway in their locale, they find the speeds to be as listed in file XR13087. At the 0.025 level, and assuming a normal distribution of vehicle speeds, could they be mistaken in their conclusion that too much variability exists in the speeds of vehicles passing this location?
A computer and statistical software.