Discrete VS Continuous?
Discrete = counts / whole numbers (0, 1, 2, …)
Continuous = can take any value on a scale (1.73, 1.731, …)
What are the 4 measurement levels?
Nominal (names),
Ordinal (ranked),
Interval (equal gaps, no true zero),
Ratio (equal gaps + true zero).
Difference: Nominal vs Ordinal?
Nominal = no order (e.g., gender categories).
Ordinal = ordered (e.g., low/med/high).
Difference: Interval vs Ratio?
Interval = no true zero (°C).
Ratio = true zero (kg, time, income).
Categorical vs Continuous?
Categorical = groups/labels (nominal/ordinal).
Continuous = numeric scale (interval/ratio).
Independent vs Dependent variable?
IV/predictor = input/explanatory.
DV/outcome = what you predict/explain.
What is the standard error (SE)?
Estimated SD of a statistic (often the mean); smaller SE = more precise estimate.
Type I vs Type II error?
Type I: false positive (reject true H₀).
Type II: false negative (fail to reject false H₀).
Linear regression DV measurement level?
DV should be continuous (interval/ratio).
Linear regression IVs: what types can they be?
Continuous or categorical (dummy-coded)
Standardised vs unstandardised coefficients?
Unstandardised β: change in Y units per 1-unit X.
Standardised β: change in SD units per 1 SD X (compare predictors).
Logistic regression DV measurement level?
Categorical, typically binary nominal (0/1).
What does categorical mean?
A variable is categorical when each value is a label/group you belong to.
eg.
Gender category: male / female / nonbinary
Outcome: pass / fail
Difference between nominal and categorical?
Categorical = the big umbrella: variables made of categories/labels (not amounts).
Nominal = a specific measurement level under categorical: categories with no natural order.
Examples:
Gender → categorical, nominal
Yes/No outcome → categorical, nominal
Low/Medium/High pain → categorical, ordinal (still categorical, but ordered)