Problema Solution

3)Assume that we have a batch of 100, 000 heart pacemakers, including 99, 950 that are

good (G) and 50 that are defective (D)

a)If two of those 100,000 pacemakers are randomly selected without replacement, find

the probability that they are both good?

Answer provided by our tutors

We are dealing with conditional probability.

P(2 are good) = P(the first selected is good)*P(the second selected is good on the condition that the first is good)

P(2 are good) = (99,950/100,000)*(99,949/99,999)

P(2 are good) =0.999000245 or 99.9% is the probability that both are good.