From Randomness to Probability Flashcards
Complement Rule of Probability
P(not A) = P(Ac) = 1 - P(A)
Addition Rule of Probability
P(A or B) = P(A) + P(B)
provided A and B are disjoint.
Specific Multiplication Rule of Probability
P (A and B) = P(A) x P(B)
provided A and B are independent.
Random phenomenon
A phenomenon is this if we know what outcomes could happen, but not which particular values will happen.
Trial
A single attempt or realization of a random phenomenon.
Outcome
The value measured, observed, or reported for an individual instance of a trial.
Event
A collection of outcomes. Usually, these are attached to probabilities and denoted with bold capitol letters such as A, B, or C.
Sample Space
The collection of all possible outcome values: the whole collection has a probability of 1.
Law of Large Numbers
The long-run relative frequency of an event’s occurrence gets closer and closer to the true relative frequency as the number of trials increases.
Independence (informal)
Two events are this if learning that one event occurs does not change the probability that the other event occurs.
Probability
A number between 0 and 1 that reports the likelihood of that event’s occurence.
Empirical probability
When the probability comes from the long-run relative frequency of the event’s occurrence.
Theoretical probability
When the probability comes from a model (such as equally likely outcomes).
Probability Assignment Rule
The probability of the entire sample space must be 1.
Disjoint (mutually exclusive)
Two events are this if they share no outcomes in common: knowing that A occurs tells us that B cannot occur.
