Answer
Three approaches to probability:
(1) Classical probability
(2) the relative frequency concept of probability
(3) the subjective probability concept.
Work Step by Step
1) The classical probability is applied to compute the probabilities of events for an experiment for which all outcomes are equally likely. For example, head and tail equally likely outcomes when a fair coin is tossed once. Each of these two outcomes has the same chance of occurrence.
2) The relative frequency as an approximation of probability is computed when an experiment is repeated n times and an event A is observed f times where f is the frequency, then,
$P(A) = \frac{f}{n} = \frac{Frequency of A}{sample size}$
For example,
Ten of the 500 randomly selected trucks manufactured at a certain factory are found to be lemons. Assuming that lemons are manufactured randomly, what is the probability that the next car manufactured at this factory is a lemon?
Let n denote the total number of trucks in the sample and f the number of lemons in n.
n = 500, f = 10
Using the relative frequency concept of probability, we obtain
P(next truck is a lemon) = $\frac{10}{500}$
3) Subjective probability is the probability assigned to an event based on subjective judgment, experience, information and belief. There are no definite rules to assign such probabilities. For example, subjective probability is used when we want to find out the probability that Carol, who is taking a chemistry subject, will acquire an A in the subject.
