A large lot of items includes 10% defectives. Thus the chance of selecting a defective item is 0.1 and conversely, the chance of selecting a good item is 0.9. Compute to 4 decimal places, the chance of getting 1 or 2 defectives. Consider n=10.
+129849 Probability of selecting 1 defective item from any 10 =
C(10,1) * (.10) * (.90)^9 = about .3874
Probability of selecting 2 defective items from any 10 =
C(10,2) * (.10)^2 * (.90)^8 = about .1937
So....the probability of getting 1 OR 2 defectives = about .3874 + .1937 = .5811
