Question 1160247: 135 UB students were surveyed and asked how many hours a week they spent studying. The results are in the table below?
Less than 5hrs (5 to10hrs) (More than 10) Total
Male (M) 25 25 20 70
Fmale (F) 20 30 15 65
Total 45 55 35 135
a) Complete the joint and marginal probability.
b) Find the probability that a student studied 5 to 10 hours.
c) Find the probability that a student is a male and spends less than 5 hours studying.
d) Find the probability that a student is a female or spends more than 10 hours studying.
e) Find the probability that a student spends more than 10 hours studying given that the student is a female?
f) Find the probability that a student is a male given that he spends less than 5 hours studying.
Answer by Boreal(15235)   (Show Source):
You can put this solution on YOUR website! Less than 5hrs. (5 to10hrs) (More than 10) Total
Male (M) 25 ------- 25----------20----------- 70
Female (F) 20-------30-------- - 15---------- 65
Total ---45------55--------- -35-----------135
b. 5-10 hours is 55/135 or 11/27
c.this is 25/135 or 5/27
d. female is 65, more than 10 hours is 35, and that is 100. Subtract both (double counted) 15=85/135 or 17/27
e. Given female (65), and more than 10 hours (15) so that joint is 15/65 or 3/13
f. given less than 5 hours (45) probability a male is 25, so 25/45 or 5/9.
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