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## SAT - Math - Probability

### Results on the Bar Exam of Law School Graduates The table above summarizes the results of 200 (more)

 Passed Bar Exam Did not pass bar exa Took review course 18 82 Did not take review course 7 93

Results on the Bar Exam of Law School Graduates. The table above summarizes the results of 200 law school graduates who took the bar exam. If one of the surveyed graduates who passed the bar exam is chosen at random for an interview, what is the probability that the person chosen did not take the review course?

x= total Law School Graduates- Did not pass bar exam- who took review course who passed the bar exam. x= 200-175-18 x=7

### The data in the table above were produced by a sleep researcher studying the number of dreams people recall when asked to record their dreams for one week. (more)

The data in the table above were produced by a sleep researcher studying the number of dreams people recall when asked to record their dreams for one week. Group X consisted of 100 people who observed early bedtimes, and Group Y consisted of 100 people who observed later bedtimes. if a person is chosen at random from those who recalled at least 1 dream, what is the probability that the person belonged to Group Y?

Event X: A person chosen randomly recalls dream at least once

Event Y: Probability that the person belonged to Group Y

P(Y) = 100/200 = 1/2

P(X) = 1 - (15+21) / 200 = 1- 36/200 = 1-9/50 = 41/50

P(X|Y) = (11 + 68) / 100 = 79/100

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