1.If x, the time (in minutes) to complete an change job at certain auto service station, is uniformly distributed over the interval 20 to 30, then the probability that an oil change job will be completed 24 minutes or more is __________________.
2.The number of finance majors within the School of Business is an example of _______.
a discrete random variable 

a continuous random variable 

the normal distribution 

the uniform distribution 3. Sure Stone Tire Company has established that the useful life of a particular brand of its automobile tires is normally distributed with a mean of 40,000 miles and a standard deviation of 5000 miles. What is the probability that a randomly selected tire of this brand has a life of at least 50,000 miles?
