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Chapter 7: Probability
persons may have different measure of beliefs for the occurrence of a
particular event. An example of a subjective probability is a probability
value that you assign to the chance of a particular aromatic therapy being
effective in reducing your blood pressure (stress). This will be based on
your own experiences – number of hours of therapy, initial stress level, time
of day the therapy is administered, time of the year therapy is administered,
etc. Subjective probability cannot be uniformly used to define the chance of
the occurrence of an event because the value may be different for different
people.
Section Review
7-8 Some Basic Rules of Probability
Following are four basic laws of probability:
Rule 1:
If the probability of an event is 1, then the event is certain to occur.
For example, the probability of each of us dying is 1. We know that the
event of dying is certain to occur if we are currently alive.
Rule 2:
If the probability of an event is 0, then the event will never occur.
For example, the probability of a naturalized US citizen becoming the
President of the United States is zero. This is the decree of the United States
Constitution.
Rule 3:
The probability of any event must assume a value between 0 and 1,
inclusively.
For example, the probability of it raining today is 0.4 = 40%. We cannot be
more than 100 percent certain that it will rain, nor can we be less than 0
percent certain that it will rain.
e-Self Review