Given the information in Exercise 13.87 and data file XR13087, determine the 95% confidence interval for the population variance of the speeds of vehicles passing this location on the urban interstate.
In exercise
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.
A computer and statistical software.