Question

A sample of 4 different calculators is randomly selected from a group containing 42 that are defective and 20 that have no defects. What is the probability that all four of the calculators selected are defective? No replacement. Round to four decimal places.

Answer 1

0.2006

Explanation:

The probability the first calculator is defective is 42/62.

The probability the second calculator is defective is 41/61.

The probability the third calculator is defective is 40/60.

The probability the fourth calculator is defective is 39/59.

The probability all four calculators are defective:

(42/62) (41/61) (40/60) (39/59) = 0.2006