PROBABLITY

PROBABLITY

1. Probablity of any event can never be less than 0 and not more than 1 0<= P(E)<=1

2. Equally likely events: The different outcomes have the same as equal chance of occurence

3. Event: an outcome of a random experiment or an event is something that happened.

4. Sample space: Set of all possible outcomes of an experiment

5. Random experiment: may result in two or more outcomes: e.g. 1. tossing a coin 2. throwing a dice

6. Probablity of events

   • sum of the probablity of all events is always one, e.g. Suppose there are n events corresponding to a random experiment, them P(E1)+P(E2)+...P(En)=1
   • complemetary event : P(E)+P(E bar)=1 or P(E bar)= P(not E bar)= complimentary events
   • certain event or sure event: Probablity of an event is equal to 1
   • Impossible event: Probablity of an event is equal to 0

7. Types

   • Empirical probablity: when probablity is based on an actual experiment suppose event E is happen, when experiment is performed then P(E)=No. of times event E occured / No. of times the experiment was performed
   • Measurement probablity: when repetition of an experiment can be avoided for exact probablity. Probablity= No. of favourable outcomes/ No. of all possible outcomes
   • Classical Probablity: Probablity of an event denotes likelihood of its happening : P(E)= No. of event favourable/ Total no. of all possible event