In: Statistics and Probability
Suppose P(A)=.5, P(B)=.4 and P(A and B)=.2
a. Find P(A or B).
b. Find P (A and Bc) B complement
c. Find P(A or Bc).
d. Find P(Ac or Bc)
or represents union and 'and' represents intersection
P(A)=.5, P(B)=.4 and =.2
a. Find
Using the addition theorem
= 0.5 + 0.4 - 0.2
b. Find B complement
P(A) can be found out by adding the possible combinations of A with B and B'.
= 0.5 - 0.2
c. Find
P(B') = 1 - P(B) .....Property of complements
=1 - 0.4= 0.6
0.5 + 0.6 - 0.3
d. Find
Again we have the possible combinations of B' with A and A'
= 0.6 - 0.3 = 0.3
P(A') = 1 - P(A)
= 1 - 0.5 = 0.5
0.5 + 0.6 - 0.3
We can also use the identity
= 1 - 0.2
= 0.8