Probability: The proportion of times the event occurs in many repeated trials of a random
phenomenon.
Random samples eliminate bias from the act of choosing a sample, but they can still be wrong
because of the variability that results when we choose at random. If the variation when we take
repeat samples from the same population is too great, we can’t trust the results of any one
sample.
Chance behavior is unpredictable in the short run but has a regular and predictable pattern in the
long run.
Probability describes what happens in very many trials, and we must actually observe many trials
to pin down a probability.
We call a phenomenon random if individual outcomes are uncertain but there is nonetheless a
regular distribution of outcomes in a large number of repetitions.
The probability of any outcome of a random phenomenon is the proportion of times the outcome
would occur in a very long series of repetitions.
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
This is the end of the preview.
Sign up
to
access the rest of the document.
 Winter '11
 PattiColling
 Probability, Probability theory, random phenomenon

Click to edit the document details