Glossary Items Starting with "U"

unbiased assignment: Assigning participants to groups or conditions in such a way that the groups are statistically equivalent at the start of the study. The most common unbiased assignment method is random assignment.
univariate: Having to do with one variable. For example, a univariate distribution would provide the distribution for a single variable.
univariate designs: See single-variable design.
unobtrusive measure: Any measure that can be taken on participants without them being aware they are being measured.
unobtrusive observer: Anyone who is able to observe the behavior of participants without them being aware they are being observed.