Computer keyboard failures can be attributed to electrical defects or mechanical defects. A repair facility currently has 25 failed keyboards, 10 of which have electrical defects and 15 of which have mechanical defects. (b)
In how many ways can a sample of 7 keyboards be selected so that exactly two have an electrical defect?
(c)
If a sample of 7 keyboards is randomly selected, what is the probability that at least 6 of these will have a mechanical defect? (Round your answer to four decimal places.)