probability Flashcards
result of an observation or experiment, or the descriptor of some potential outcome
event
a subset of the set of all possible outcomes of a probabilistic experiment
event
the measure of the likelihood of an event happening
probability
measures the certainty of an event
probability
This means that both events must be met for it to count as one value
Intersection (A∩B)
This means that the fulfillment of only A, only B, or both A and B is accounted for
Union (A∪B)
This means that the non-fulfillment or the converse/opposite event of A is the trigger for this operation.
Complement (Ā)
A and B are treated as separate events, cannot happen at the same time
mutually exclusive
represents all the outcomes that could possibly occur
sample space
P(S) = 1
an event that can never occur and has a probability of 0, whereas most events have probabilities between the value 0 and 1,
null event
A ∩ A^c = ɸ
when two events are mutually exclusive, the additive rule of probability states that the probability that either of the two events will occur is equal to the sum of the probabilities of the individual events
additive rule of probability
P(A∪B) = P(A) + P(B)
express answers in
*express answers in probability as either decimal (2 dec places) or percentage (%)
type of probability wherein the probability of one event is directly influenced by the probability of another event
conditional probability
This is expressed as P(A|B) wherein the probability of an event A is influenced by the existence of event B. How do you read it
“probability of A withing the existence of B”
*taken into account the multiplicative rule of probability
this states that the probability that two events A and B will both occur is equal to the probability of B multiplied by the conditional probability of A given that B has already occurred
multiplicative probability
a fundamental rule relating marginal probabilities to conditional probabilities
total probability
a set if events that all amount to the sum of 1 - meaning that there are no other possible outcomes and it must fall under one of the categories
exhaustive
S = A1 ∪ A2 ∪ A3
this states that the probability that two events A and B will both occur is equal to the probability of B
multiplied by the conditional probability of A given that B has already occurred
total probability rule
this is a function wherein you want to compare the probability of occurrence of an event between
two groups
relative risk
(is between an exposed group and an unexposed group)
odds ratio is aka
relative odds
if an event takes place with probability p, then the odds in favor of the event are the probability that the event will occur divided by the probability the event will not occur, or p/(1–p) to 1
odds ratio
*calculate for the odds in favor of the event
odds ratio and relative risk is normally used for
RR - cohort studies
OR - case-control studies
