Question

Printed circuit cards are placed in a functional test after being populated with semiconductor chips. A lot contains 140 cards, and 20 are selected without replacement for functional testing. a. If 20 cards are defective, what is the probability that at least 1 defective card is in the sample

Answer 1

The probability that at least 1 defective card is in the sample is
`0.9644`

Explanation:

Here

N = 140

and n = 20

We will use the below given formula

P(at least 1 defective) = 1 - P( 0 defectives)

P( 0 defectives) =

`= (^(20)C_0 * ^(120)C_(20))/( ^(140)C_(20))\\= 0.0356 1-0.0356 \\= 0.9644`