Suppose that the speed at which cars go on the freeway is normally distributed with mean 80 mph and standard deviation 8 miles per hour. Let X be the speed for a randomly selected car. Round all...

Suppose that the speed at which cars go on the freeway is normally distributed with mean 80 mph and standard deviation 8 miles per hour. Let X be the speed for a randomly selected car. Round all answers to 4 decimal places where possible.


a. What is the distribution of X? X ~ N(,)


b. If one car is randomly chosen, find the probability that it is traveling more than 81 mph.


c. If one of the cars is randomly chosen, find the probability that it is traveling between 81 and 84 mph.


d. 74% of all cars travel at least how fast on the freeway?  mph.