Flash Cards: Probability

Probability is the measure of the likelihood that an event will occur, expressed as a number between 0 and 1.

Equally likely outcomes are outcomes in an experiment that have the same chance of occurring.

Empirical probability is defined as P(E) = (Number of trials in which the event happened) / (Total number of trials).

A sure event is one that is certain to happen and has a probability of 1.

An impossible event cannot happen and has a probability of 0.

Complementary events are two outcomes of an event that cannot occur at the same time. P(E) + P(not E) = 1.

P(red) = 4/5, since there are 4 favorable outcomes out of 5 total possible outcomes.

P(head) = 1/2, as there are two equally likely outcomes: heads or tails.

The outcomes are 1, 2, 3, 4, 5, and 6, each with an equal probability of 1/6.

The combinations to get 8 are (2,6), (3,5), (4,4), (5,3), and (6,2), hence P(sum=8) = 5/36.

If there are 365 days, the probability is P(same) = 1 - (364/365) = 1/365.

P(girl) = 25/40 = 5/8.

P(white) = 2/9.

P(at least one head) = 3/4.

This means that if one event occurs, the other cannot occur, representing certainty that one of them will happen.

P(Ace) = 4/52 = 1/13.

Probability values range from 0 to 1, inclusive.

Assuming all outcomes are equally likely when they are not.