Quantitative Methods - 3.1 - Conditional and Joint Probabilities Flashcards
define random variable
an uncertain quantity/number
define an outcome
an observed value of a random variable
define an event
a single outcome or set of outcomes
what are mutually exclusive events?
events that can’t happen at the same time
what are exhaustive events?
those that include all potential outcomes
what are the two defining properties of probability?
- the probability of occurrence is between 0 and 1
- in a set of events that are mutually exclusive and exhaustive, the probabilities of the events sum to 1
how is an empirical probability established?
established by analyzing past data (outcomes)
how is a priori probability determined?
they are deductive and based on reasoning (not data)
what does subjective probability involve?
using personal judgement
what examples of probability are priori and empirical?
objective
what is unconditional probability? AKA?
(AKA marginal)
- probability of an event regardless of the past or future occurrence of other events
what is conditional probability? AKA?
(AKA likelihood)
- the occurrence of one event affects the probability of the occurrence of another event
how is conditional probability written symbollically?
Prob(A|B) or P(A|B)
when is the addition rule of probability used?
to determine the probability that at least one of two events will occur
- P (A or B)
what is the joint probability?
the probability that 2 sets of events will both occur
