chapter  56
Pages 6

An independent event is one in which the probability of an event happening does not affect the probability of another event happening. If 5 transistors are taken at random from a batch of transistors and the probability of a defective transistor p1 is determined and the process is repeated after the original 5 have been replaced in the batch to give p2, then p1 is equal to p2. Since the 5 transistors are replaced between draws, the second selection is said to be with replacement.

Conditional probability is concerned with the probability of say event B occurring, given that event A has already taken place.