This is the eighth page of the series of free video lessons, "Statistics Lectures".
Statistics - Lecture 21
The Basics of Probability
Probability is a measure of the likelihood of an event.
A sample space is a collection of all possible outcomes.
An event with a probability of 0 is impossible (it will never happen).
An event with a probability of 1 is certain (it will always occur).
Statistics - Lecture 22
Addition Rule (Probability "or")
Two events are mutually exclusive if they cannot occur at the same time.
Addition rule for mutually exclusive events:
P(A or B) = P(A) + P(B)
Statistics - Lecture 23
Multiplication Rule (Probability "and")
Two events are independent if they do not affect one another.
Multiplication Rule for independent events:
P(A and B) = P(A) x P(B)
General Multiplication Rule for Dependent or Conditional Event:
P(A and B) = P(A) x P(B|A)
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