Tropical rainforests are located in areas near the Equator. The temperature in a typical rainforest ranges from 20 to 30°C, and the humidity is usually between 77% and 88%.29 The mean amount of rain per year in any one rainforest is m 5 155 inches with standard deviation s 5 35 inches. Suppose 30 rainforests are selected at random and the amount of rain per year is recorded for each.
a. What is the probability that the mean rainfall per year for the 30 rainforests is more than 170 inches?
b. What is the probability that the mean rainfall is between 140 and 150 inches?
c. Find a value r such that the probability that the mean rainfall is less than r is 0.001
An office manager has several computers running distributed programs. Because of the demands on the system, the machines may crash at various times during the day and require a hard reset. The probability distribution for the number of times a randomly selected machine crashes during a day, X, is given in the table below.
a. Find the mean, variance, and standard deviation for the number of crashes by a single machine during a day.
b. Suppose n = 2 machines are selected at random. Find the sampling distribution of the statistic T, the total number of crashes for the two machines.