Q1(10). A health club states the time that their clients spend in the club follows a uniform distribution on interval (20, 100) mins.

1(4). Find the probability that one randomly selected client spend more than 80 mins in the club.

2(6). Consider a random sample of 36 clients, find the probability that the average time spent in the club are between 56 mins and 68 mins, inclusive.

Q4(9). The average number of serious accidents occurred on one highway is 2.1 per week. Assume the number of serious accidents is independent from week to week. Let X be the number of serious accident in one randomly selected week.

1(2). Find the mean and variance for X.

2(3). Find the probability that the number of serious accidents is exactly three in this randomly selected week.

3(4). Find the probability that the number of serious accident is greater than two and less than six, in this randomly selected week.