4. Whether a customer at a carry-out restaurant leaves a tip is a random variable. The probability that a customer leaves a tip is 0.42. The probability that one customer leaves a tip is independent of whether another customer leaves a tip. Let leaving a tip represent a I'success\" and not leaving a tip represent a "failure." Does this problem describe a discrete or continuous random variable? b. What kind probability distribution ts the random variable described in this problem? What is the probability that a customer does not leave a tip? Calculate the mean and variance of this distribution. e. What is the probability that on a day with 100 customers, exactly 50 of them leave a tip? 5\" no