5. The incidence rate of leukemia in a certain place is 10/100,000, and a study randomly investigates 100,000 participants.

(a) What is the distribution of the number of incidence cases of leukemia?

What are the parameters that determine this distribution?

(b) Determine the expected value and variance of the number of incidence cases of leukemia, and describe the relationship between the expected value and variance.

(c) Calculate the probability that no leukemia case is found.

(d) Calculate the probability that the number of incidence cases of leukemia is no more than two.