1. Testing a pain reliever using 840 people to determine if it is effective. The random variable represents the number of people who find the pain reliever to be effective.
a. binomial experiment
b. not a binomial experiment
A test consists of 10 true or false questions. To pass the test a student must answer at least eight questions correctly. If the student guesses on each question, what is the probability that the student will pass the test?
a. 0.20
b. 0.055
c. 0.08
d. 0.8
2 answers
1. a?
To have 8 or more correct, the student must get exactly 8 correct OR exactly 9 correct OR exactly 10 correct
= C(10,8)(1/2)^8 (1/2)^2 + C(10,9) (1/2)^10 + C(10,10)(1/2)^10
= (1/2)^10(45 + 10 + 1)
= 56/1024
= 7/128
= C(10,8)(1/2)^8 (1/2)^2 + C(10,9) (1/2)^10 + C(10,10)(1/2)^10
= (1/2)^10(45 + 10 + 1)
= 56/1024
= 7/128
4 answers