Probability

Probability

1. Theoretical Probability

   • Number of trials in P(E) = Which the event happened/Total number of trials.

2. Experimental Probability

   • What actually happens in an experiment. Number of outcomes P(E) = favourable to E/Number of all possible outcomes of the experiment

3. Definitions

   • Elementary Event Event having only one outcome of the experiment.
   • Complementary Event For event E, complement event, P(E)= 1. P(E).
   • Sure or Certain Event When event having probability to occur as 1.

4. Values

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

5. Examples

   • CARD; What is the probability of getting an ace from a pack of 52 cards? SOLUTION: Number of favourable outcomes = 4 Number of possible outcomes = 52 P(E) = 4/52 = 1/13
   • DICE; Two dice are rolled ,what is the probability of getting 12 as a sum? SOLUTION: Number of possible outcomes = 6*6 = 36. Number of favourable outcomes = 1 i.e, (6,6) P(E) = 1/36.