5.2-08 – Introductory Statistics – Sheldon M. Ross

Question:

Suppose that 2 batteries are randomly chosen from a bin containing 10 batteries, of which 7 are good and 3 are defective. Let X denote the number of defective batteries chosen. Give the possible values of X along with their probabilities.

Solution:

Let X = the number of defective batteries chosen

X	P (X)
0	7/10 * 6/9 = 42/90
1	7/10 * 3/9 + 3/10 * 7/9 = 42/90
2	3/10 * 2/9 = 6/90
	1.00