Flashcards: Probability & Statistics

The ratio of number of favorable outcomes to the total number of possible outcomes.

The range of values of a random variable.

In logic and probability theory, two propositions (or events) are disjoint if they cannot both be true (occur).

If events A and B come from the same sample space, the probability that event A and/or event B occur is equal to the probability that event A occurs plus the probability that event B occurs minus the probability that both events A and B occur. P(A ∪ B) = P(A) + P(B) - P(A ∩ B)

A set of outcomes of an experiment (a subset of the sample space) to which a probability is assigned.

Represented by A $\cup$ B. Here, P (A) is the probability of event A, P (B) is the probability of event B.

A statistical population in such a way that every possible sample that could be selected has a predetermined probability of being selected.

The probability that Events A and B both occur is the probability of the intersection of A and B.

A notation for the probability of B given A. In the case where events A and B are independent (where event A has no effect on the probability of event B), the conditional probability of event B given event A is simply the probability of event B, that is P(B).

All outcomes that are NOT the event. So the Complement of an event is all the other outcomes (not the ones we want).

The probability of an event ( A ), given that another ( B ) has already occurred.

Two-Way Frequency Table: You can probably guess that a two-way frequency table will deal with two variables.

When two events are said to be independent of each other, what this means is that the probability that one event occurs in no way affects the probability of the other event occurring.

Two events are dependent if the outcome or occurrence of the first affects the outcome or occurrence of the second so that the probability is changed.

When running independent experiments, the usage of the product formula P(A∩B) = P(A) P(B) is justified on combinatorial grounds. For a pair of independent events, the formula serves as a definition.