Question

Suppose that a large and complex piece of software has 10,000 bugs, each with an MTBF of 1,000,000 hours. Then you expect to find a particular bug after 1,000,000 hours of testing, and—since there are 10,000 bugs—you expect to find one bug for every 100 hours of testing. Suppose the good guys do 200,000 hours of testing while the bad "guy," Trudy, does 400 hours of testing.

a. How many bugs should Trudy find? How many bugs should the good guys find?

b. What is the probability that Trudy finds at least one bug that the good guys did not?