Question

A quality control inspector has drawn a sample of 15 light bulbs from a recent production lot. Suppose that 60% of the bulbs in the lot are defective. What is the expected value of the number of defective bulbs in the sample

Answer 1

9

Explanation:

Expected number of defective is given as :

N x P = np

Where = number of the sample drawn from the production lot

P= percentage of bulbs In The lot which are defective

N = 15

P = 60% = 0.60

So when we do the multiplication,

We have:

NP = 15x0.60

= 9

So in conclusion the expected value of defective bulbs in the sample is 9.