Psycholgy AQA A: Choosing A Statistical Test

A set of data is said to be ordinal if the values / observations belonging to it can be ranked (put in order) or have a rating scale attached. You can count and order, but not measure, ordinal data.

A  set of data is said to be nominal if the values / observations belonging to it can be assigned a code in the form of a number where the numbers are simply labels. You can count but not order or measure nominal data.

For example, Males could be expressed as 0 and females 1.

Level of measurement: Nominal

Note: Chi-squared is the only stats test that is nominal.

Design: Independent

(To remember: CIN - Chi-squared, Independent, Nominal)

Level of Measurement: Ordinal

Shows the relationship between two variables: Correlation

(To remember: SOC - Spearman's Rho, Ordinal, Correlation)

Level of Measurement: Ordinal

Design: Independent Groups

(To remember: MOI - Mann-Whitney, Ordinal, Independent)

Level of Measurement: Ordinal

Design: Repeated Measure

(To remember: WOR - Wilcoxan, Ordinal, Repeated)