Glossary

Between-subjects design:

A between-subjects design consists of two or more groups of subjects, with each group of subjects participating in only one test condition.

Categorical variable (also called nominal variable)

Categorical variables cannot be sequentially ordered using a mathematical method.

Examples:

· gender (male/female),

· ethnicity (Caucasian, Hispanic, African/American)

Continuous variable

Continuous variables can be measured and sequenced numerically, but cannot be equally spaced. [13]

Examples:

• weight
• number of seconds to perform a task

Interval variable

Interval variables consist of two or more ranges of equally spaced values.

Example:

• income ranges such as $10,000 – 15,000, $15,000-20,000, etc.

In this example, the ranges are defined in $5000 increments. The equality of the increments characterize the interval metric.

Ordinal variable

Ordinal variables are non-numerical values that can be sequentially ordered, but the space between values is not equal.

Example:

• education level (completed grade school, high school, some college, 4 year degree, etc.)

Within-subjects design:

A within-subjects design consists of one group of subjects who participate in more than one test condition.