Overall, the number of work-hours involved in the festival preparation is normally distributed around 20 hours with a standard deviation of 5 hours. a) What's the probability that the mean number of work-hours will be between 15 and 18? b) The members at or below the 25%ile of number of worked-hours must attend a one-on- one meeting with their supervisor. At least how many work-hours should you have in order to avoid attending such session? c) How likely (what is the probability) is it to have the number of involved work-hours over 20? d) How likely is it (what is the probability) that some employee will have his/her involved work-hours between 15 and 26? e) What is the 75%ile?