Statistics notes—Choosing valid statistical methods

Statistical validity depends on data type, distribution, independence, sample size and whether the question asks for a difference or relationship.

State why a method fits before calculating, then link the outcome to the biological claim.

Chi-squared suits category counts, a t-test suits two means, and Spearman suits ranked or non-normal monotonic data.

A method can be mathematically executable but biologically invalid if its assumptions are ignored.