PROBABILITY

PROBABILITY

1. DEFINATIONS

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

2. THEORITICAL PROBABILITY

   • 0< P(E) < 1 What we expect to happen in an experiment Number of trials in P(E) = which the event happened / Total number of trials.

3. EXPERIMENTAL PROBABILITY

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

4. VALUE

   • 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 probabilty of getting an ace from a pack of 52 cards? SOLUTION: 4 Number of possible outcomes = 52 P(E) = 4/52 = 1/13
   • COIN: When a coin is tossed, what would be the probability of appearing head? SOLUTION: Total outcomes + 2 i.e. (H,T) Favourable outcomes = 1 P(E) = 1/2
   • DICE: Two dice are rolled, what is the probability of getting 12 as a sum ? SOLUTION: Number of favourable outcomes = 1 i.e. (6,6) P(E) = 1/36