Lecture 3: Describing Data-Categorical Variables

frequency distribution

the sum of all observed cases and distributes them

relative frequency distribution

expressed as proportions rather than count

two-way contingency table

shows the frequency of two variables (joint distribution)

marginal/unconditional

denominator is total and not restricted

conditional

different denominator by restricted conditions

equal

if all proportions are _______, then the variables are independent to one another

not equal

if all proportions are ___________, then the variables are associated to one another (i.e. not independent)

independent

two events, A and B, are said to be __________ if knowing that one will occur (or has occured) does not change the probability that the other occurs

P(A|B) = P(A)

independent event probability notation

P(A|B)

probability of event A given event B took place

P(A)

marginal probability of A