Question

A sample of 4 items is selected at random from a box containing 12 items in which 5 are defective. Find probability distribution of the number of defective items.

Answer 1

Step-by-step explanation:

selected from among 12 = 12/(81)(4!) = 495. Those possible with 0 defective items = [5!/(5) (017/(31)(41) = 35. Those possible with 1 defective item = [5!/(41) (11[7V(49(31) = 175. Those possible with 2 defective items = [5/(31) (2)][7/(51)(21) = 210. Those possible with 3 defective items = [5/(2) (3)|[7/(61)(11) = 70. Those possible with 4 defective items = [5!/(11) (41)|[7U(79(01) = 5. Thus, there are 460 possible combinations of 4 items, selected as described, which include at least 1 and up to 4 defective items. Just 35 possible combinations of 4 items include none that are defective.