Statistical Tests

Time series analysis is the study of observations recorded in chronological order, like daily sales, hourly electricity demand or monthly hospital visits, so you … Read more

Stepwise regression is a procedure that builds a multiple regression model one variable at a time, adding or removing predictors according to a significance … Read more

Ordinal logistic regression predicts an ordered categorical outcome — a 1-to-5 satisfaction rating, a severity band, an exam grade — by modelling the probability … Read more

A Poisson regression is a generalized linear model with a log link, used when your outcome is a non-negative integer count of events, such … Read more

Hierarchical regression lets you enter predictors in blocks, then measure what each new block adds on top of everything already in the model. R … Read more

Testing moderation means checking whether the link between your predictor and your outcome changes depending on a third variable. You do it by multiplying … Read more

The difference between z test and t test comes down to a single input: whether you know the population standard deviation. Use a z-test … Read more

You interpret a mediation analysis result by finding the indirect effect, the a times b path, and checking whether its bootstrap confidence interval contains … Read more

To run a mixed ANOVA with between and within factors, you enter every repeated measure as its own column, then open Analyze > General … Read more

Cramer’s V measures how strongly two categorical variables are associated, on a scale from 0 to 1, using the chi-square statistic from a contingency … Read more