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 distance in fresh snow is known to be 215 meters with a standard deviation of σ = 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 212.9 meters (a) What are the appropriate null and alternative hypotheses to test the manufac- turer's claim? (b) Using the sample results and assuming that stopping distance is a Normally distributed random variable, what is the value of the test statistic? (c) What is the value of the P-value?

Answer 1

2.-5 not