Converting an hour to minutes the probability of completing the exam in an hour or less is P x 60 Before finding this probability the random variable x needs to be converted to th normal random variable z so that a table of probabilities can be used Recall the formula to convert an x value to the normal random variable z where x is the value that needs to be converted u is the population mean and a is the population standard deviation Z The mean was given to be 100 minutes and the standard deviation was given to be 20 minutes Find the value of the z statistic corresponding to x 60 x G Z 60 X H 20 Thus the new probability statement using the normal random variable z is S