Mrs. Myles gave the same test to both her first and third-period class. In the first period, the mean was 75 and the range was 30. In the third period, the mean was 85 and the range was 50.

Which is a true statement?

A) Most of the third period scored in the '80s.

B) More people had a score in the 70's in the first period.

C) On average, the third period did better than the first period.

D) On average, the first period did better than the third period.

Amachine that produces a special type of transistor (a component of computers) has a 2% defective rate. the production is considered a random process where each transistor is independent of the others. (a) what is the probability that the 10th transistor produced is the first with a defect? (b) what is the probability that the machine produces no defective transistors in a batch of 100? (c) on average, how many transistors would you expect to be produced before the first with a defect? what is the standard deviation? (d) another machine that also produces transistors has a 5% defective rate where each transistor is produced independent of the others. on average how many transistors would you expect to be produced with this machine before the first with a defect? what is the standard deviation? (e) based on your answers to parts (c) and (d), how does increasing the probability of an event a↵ect the mean and standard deviation of the wait time until success?