If the probability of full recovery following polio is 0.3 and the probability of paial recovery is 0.4, then the total probability of full or paial recovery following polio is:

In case of mutually exclusive events, for example total and paial recovery, the total probability can be calculated by applying the law of addition. i.e. P (full or paial recovery)= P(full recovery)+ P(paial recovery) = 0.4+0.3=0.7 Ref: Medical biostatistics, 1st edition pg: 191