Here are the solutions to the midterm question posted in class:

a)      P(N) = 0.6 P(CC | N) = 0.4 P(N and CC) = 0.24

P(R) = 0.4 P(CC | R) = 0.7 P(R and CC) = 0.28

P(CC) = 0.52

 

N

R

Total

CC

24

28

52

Not CC

36

12

48

Total

60

40

100

b)      P(R | not CC) = 12/48 = 0.25

c)      P(N or not CC) = 0.6 + 0.48 – 0.36 = 0.72

d)     P(N and not CC) = 0.36

e)      P(R | CC) = 28/52 = 0.5385

f)       LS = P(R |not CC) = 0.25 (from part b); RS = P(R) = 0.4; LS ≠ RS; therefore, dependent events