CASE STUDY CHALLENGE

Probability: Defective Bulbs Analysis

A factory produces bulbs, of which 6% are defective bulbs in a large bulk of bulbs.

Based on the above information, answer the following questions:

Answer the following:

(i) Find the probability that in a sample of 100 bulbs selected at random, none of the bulbs is defective. (Use: e-6 = 0.0024). [1]
(ii) Find the probability that the sample of 100 bulbs has exactly two defective bulbs. [1]
(iii) (a) Find the probability that the sample of 100 bulbs will include not more than one defective bulb.

— OR —

(b) Find the mean and the variance of the distribution of number of defective bulbs in a sample of 100 bulbs.

[2]