Question

A shop receives a batch of 100 cheap lamps. The probability that a lamp is defective is 0.01. The qualities of the lamps in the batch are independent of each other. What is the probability that the batch contains two defective lamps

Answer 1

0.1849

Explanation:

Given that :

Sample size / number of trials = 100

Probability that a lamp. Is defective = 0.01

Probability that batch contains two defective lamps :

Using the binomial probability function :

P(x = x) = nCx * p^x * (1 - p)^(n-x)

P(x = 2) = 100C2 * 0.01^2 * (1 - 0.01)^(100-2)

P(x = 2) = 100C2 * 0.01^2 * 0.99^98

P(x = 2) = 4950 * 0.0001 * 0.3734642

= 0.184864779

= 0.1849