posted by Punkie on .
Could someone please tell me if I am on track with my answer?
Jack is taking a four-item true-false test. He has no knowledge about the subject of the test and decides to flip a coin to answer the items. What is the probability that he receives a perfect score? What is the probability on a 10-item test?
P(coin being correct in a 4 item t or f test) = 2/4
P(coin being correct in a 10 item t or f test) = 2/10 or 1/5
The chance that you get each question correct is 1/2. To calculate the probability of a perfect score on a 4 question test, you muliply the chance for each correct answer, sooo
1/2 X 1/2 X 1/2 X 1/2 = 1/16
On the 10 question test, it would be
1/2 X 1/2 X 1/2 X 1/2 X 1/2 X 1/2 X 1/2 X 1/2 X 1/2 X 1/2 = 1/1024
Thank you, you really helped me!
Your very welcome!