PROBABILITY

PROBABILITY

1. Types

   • EMPERICAL PROBABILITY When probability is based on an actual experiment suppose event E is happening , when experiment is performed then P(E)=No of times event E occured/ No of times the experiment was performed
   • MEASUREMENT PROBABILITY When repetition of an experiment can be avoided for exact probability. Therefore , Probability = No of favourable outcomes / No of all possible outcomes
   • CLASSICAL PROBABILITY Probability of an event denotes likelihood of its happening .Therefore , P(R) = No of event favourable/ Total no of all possible event

2. RANDOM EXPERIMENT Random experiment may result in two or more outcomes. e.g. 1) tossing a coin 2) throwing a dice

3. SAMPLE SPACE Set of all possible outcomes of an experiment.

4. EVENT: An outcomes of a random experiment or an event is something that happens.

5. EQUALLY LIKELY EVENTS The different outcomes have the same as equal chance of occurence.

6. Probability of an event can never be less than 0 and not more than 1 0≤P(E)≤1

7. PROBABILITY OF AN EVENT

   • Sum of the probability of all events is always one. e.g. Suppose there are n events orresponding to a randm experiment then P(E1)+P(E2)+P(E3)+.......+P(En)=1
   • IMPOSSIBLE EVENT Probability of an event is equal to 0.
   • CERTAIN EVENT/SURE EVENT Probability of an event is equal to 0
   • COMPLEMENTARY EVENT P(E)+P(E')=1 OR P(E')=1-P(E) here, P(E')=P(not E') =complimentary events