5.2-09 – Introductory Statistics – Sheldon M. Ross

Question:

A shipment of parts contains 120 items of which 10 are defective. Two of these items are randomly chosen and inspected. Let X denote the number that are defective. Find the probability distribution of X.

Solution:

Let X = the number of defective parts chosen

X	P (X)
0	110/120 * 109/119 = 0.8396
1	110/120 * 10/119 + 10/120 * 110/119 = 0.1540
2	10/120 * 9/119 = 0.0064
	1.0000