Question

It is known that driving can be difficult in regions where winter conditions involve snow-covered roads. For cars equipped with all-season tires traveling at 90 km/hr, the mean stopping time in fresh snow is known to be 215 meters with a standard deviation of o = 2.5 meters. It is often advocated that automobiles in such areas should be equipped with special tires to compensate for such conditions, especially with respect to stopping distance. A manufacturer of tires made for driving in fresh snow claims that vehicles equipped with their tires have a decreased stopping distance. A study was done using a random sample of 9 snow tires from the manufacturer on a snow-covered test track. The tests resulted in a mean stopping distance of t = 212.9 meters. 29. Using the sample results and assuming that stopping distance is a Normally distributed random variable, what is the value of the test statistic? A) 0.05 B) -2.52 C) -9.36 D) -1.04 E) -1.96