Examine each of these probability assignments and state what makes it improper.
(a) Concerning tomorrow's weather,
P(Rain) = .4
P(Cloudy but no rain) = .5
P(Sunny) = .2
(b) Concerning your passing of the statistics course,
P(Pass) = 1.1 P(Fail) = .1
(c) Concerning your grades in statistics and economics courses,
P(A in statistics) = .3
P(A in economics) = .6
P(A's in both statistics and economics ) = .4