The amounts of time per workout an athlete uses a stairclimber are normally distributed, with a mean of 23 minutes and a standard deviation of 5 minutes. Find the probability that a randomly selected athlete uses a stairclimber for (a) less than 20 minutes, (b) between 23 and 31 minutes. and (c) more than 30 minutes. (a) The probability that a randomly selected athlete uses a stairclimber for less than 20 minutes is D. (Round to four decimal places as needed.) xample Get more help - Clear all