PROBABILITY

PROBABILITY

1. THEORETICAL PROBABILITY

   • 0 ≤ P(E) ≤ 1 : What we expect to happen in an experiment : P(E) = Number of outcomes favourable to E/Number of all possible outcomes of the experiment

2. EXPERIMENTAL PROBABILITY

   • What actually happens in an experiment : P(E) = Number of trials in which the event happened/Total number of trials

3. RANDOM EXPERIMENT

   • Random experiment may result in two or more outcomes. Eg: (a) Tossing a coin (b) Throwing a dice

4. PROBABILITY OF EVENTS

   • Sum of probabilities of all elementary events is 1. i.e., P (E1) + P (E2) + P (E3) + ... P(En) = 1
   • CERTAIN EVENT OR SURE EVENT : Probability of an event is equal to 1
   • COMPLEMENTARY EVENT : For event E, complement event, P(Ē) = 1 - P(E)
   • ELEMENTARY EVENT : Event having only one outcome of the experiment
   • IMPOSSIBLE EVENT : Probability of an event is equal to 0