Question

A sample of 4 different calculators is randomly selected from a group containing 38 that are defective and 20 that have no defects. What is the probability that all four of the calculators selected are defective, P (4 defective) ? Hint: Without replacement and use the multiplication rule.

Answer 1

To find the probability of selecting 4 defective calculators without replacement, we can use the multiplication rule. The probability of selecting the first defective calculator is 38/58. Then, for the second defective calculator, the probability is 37/57. For the third, it's 36/56. And for the fourth, it's 35/55. To find the overall probability, we multiply these probabilities together.