Today we started to learn the terms and the basics of probability. Some key terms:
Sample space: the set of all possible outcomes for a trial.
Probability experiment: a group of trials.
Trial: one part of a probability experiment; it generates an outcome.
Outcome: one possible result of a probability experiment.
Event: a set of outcomes.
For example, if your experiment is to roll a d6 die 50 times, a trial is one roll of a die. The sample space is . One event, , might be rolling an even number. Then , and the probability of event occurring is .
We learned that a sample space is uniform if every outcome is equally likely (as they are in the example above). If the sample space is uniform, we can calculate the probability of event occurring as
This doesn’t work if the sample space is not uniform. For example, if the experiment is to roll 2 dice 50 times, then the set of all possible outcomes is . 7 is more likely to occur than 2, and so the sample space is not uniform and the formula above won’t work.