Question

Find he probability of no more than 35 defective CD's in a batch of 80 CD's if the probablility of any one CD being defective is 0.1.

Answer 1

0.999999

Explanation:

Given that :

Probability of CD being defective, p = 0.1

q = 1 - p = 1 - 0.1 = 0.9

Total number of CD's = number of trials = 80

Probability, that no more than 35 CD's are defective ;

The question satisfied the requirements for a binomial probability problem ;

Recall :

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

Hence,

P(x ≤ 35) = 80C35 * 0.1^35 * 0.9^(45)

Using calculator to save computation time :

P(x ≤ 35) = 0.999999