The experimental probability that the high temp will be below 45 F on the 29th day is, 4.5 out of 29 days, that is because 20 of the days have had lower temperatures, so they left 9 days of and from those 9 days, they could be lower or greater that 45F (50% each side), that is: 4.5/29 = 0.155 = 15.5% that is the exp probability