Probability

Probability

1. Value

   • Sum of probabilities of all elementary event is 1. For events A,B,C ; P(A)+ P(B)+ P(C) = 1

2. Definitions

   • When an event is having probability to occur as 1 then it is called a Sure or Certain Event.
   • For event E,complement event, P(E)=1-P(E)
   • Event having only one outcome of the experiment is called Elementary Event.

3. Experimental Probability

   • P(E) =Number of outcomes favourable to E divided by Number of all possible outcomes of the experiment

4. Theoretical Probability

   • Number of trials in P(E) = which the event happend divided by Total number of events

5. Examples

   • (i) Two dice are rolled, then the probability of getting 12 as a sum No. of possible outcomes=36 ; no. of favourable outcomes=1 then,P(E)=1/36
   • (ii) A coin is tossed then the probability of appearing head Total outcomes=2 ; Favourable outcomes =1 then, required probability P(E) = 1/2