unit 7 Experimental Probability-notes.pdf

Experimental Probability
1

Theoretical probability of an event is the ratio of
the number of favourable outcomes in an event to
the total number of possible outcomes, when all
possible outcomes are equally likely.
It can only be used to predict what will happen
in the long run, when events are equally likely to
occur.
2

Experimental probability is the ratio of the number
of favourable outcomes in an event to the number of
possible outcomes ﴾sample space﴿ observed in
simulations and experiments.
The experimental probability of an event Y is:
3

The probability in many situations cannot be
characterized as equally likely, such as tossing
a thumb tack to see if it lands with the point up
or down, and therefore, theoretical probability is
more difficult to determine. In such cases,
experiments may be conducted to identify the
probability.
Before conducting experiments, you should predict the
probability whenever possible, and use the experiment to
verify or refute the prediction.
4

Conclusions
7

• The probability of an event and its complement
will add up to 100% or 6/6 (1).
• The complement of an event is the
probability of that event not occurring.
ex. P(heads) ­ the complement is P(not
tossing heads).
• The more trials you do the closer the
experimental probability will be to the theoretical
probability.
8