STATISTIC MULTIPLE CHOICES (3 Questions)

Question 1:

In answering a question for a multiple choice test, a student either knows the answer with probability 0.5 or does not know with probability 0.4 and guesses the answer. Assume that a student who guesses at the answer will be correct with probability 0.20.

1. What is the probability that a student answers the multiple choice question correctly?

A. 0.17 B. 0.50. C. 0.60. D. 0.83

2. If a student answered a question correctly, what is the probability that s/he knew the answer to the question?.

A. 0.17. B. 0.50. C. 0.60. D. 0.83

Question 2:

How many different arrangements are there of the letters A, B, C, D, E, F for which E is not last in line?

A. 120. B. 240 C. 600 D. 720

Question 3.

A company has 2 machines that produce widgets. An older machine produces 23% defective widgets, while the new machine produces only 8% defective widgets. In addition, the new machine produces 3 times as many widgets as the older machine does.

1.Given a randomly chosen widget was tested and found to be defective, what is the probability it was produced by the new machine?

A .0.08. B. 0.15. C. 0.489. D.0.511