Probabilty
Theoretical Probabilty
What we expect to happen in an experiment
What we expect to happen in an experiment
P(E)= which the event happened/
Total number of trials
Experimental Probability
What actually happens in an experiment
P(E)= Number of outcomes favorable to E / Number of all possible outcomes of the experiment
Value
Sum of probabilities of all elementary events is 1. For events A, B, C; P(A) + P(B) + P(C) = 1
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
Event having probability to occur as 1
Examples
Dice
Coin
Card
Two dice are rolled, what is probability of getting 13 as a sum?
Solution : Number of Possible outcomes= 6^2
= 36
Number of favorable outcomes= 0
As addition of no two number on the dice will give sum = 13 is not possible
P(E)= 0/36= 0
When a coin is tossed, what would be the probability of appearing head ?
Solution : Total outcomes = 2
Favorable outcomes = 1
Required Prob. P(E) = 1/2
What is the probability of getting an ace from a pack of 52 cards?
Solution : Number of favorable outcomes = 4
Number of possible outcomes = 52
P(E) = = 4/52 = 1/13