Question

A quarter back completes 14% of his passes. We want to observe this quarterback during one game to see how many pass attempts he makes before completing one pass. What is the probability that the quarterback throws exactly 7 incomplete passes before he has a completion? (In other words, his first complete pass occurs on the 8th try).

Answer 1

The probability is 0.0487

Explanation:

For the quarterback there is a probability of 0.14 to complete the pass and a probability of (1-0.14) to doesn't complete the pass.

So, the probability that the quarterback throws exactly 7 incomplete passes before he has a completion is:

`P = (1-0.14)^(7)*0.14`

Because we multiply by (1-0.14) for every incomplete pass, in this case 7, and we multiply by 0.14 for the first complete pass. Then, the probability is:

`P = (1-0.14)^(7)*0.14 = 0.0487`