In which experimental design is a single, categorical extraneous variable that might affect test units' responses to the treatment identified and the effects isolated by being blocked out?
A) completely randomized design
B) factorial design
C) randomized-block design
D) interactive block design

Question

Quizplus · Accepted Answer

In the randomized-block design, a single extraneous variable is identified and test units are grouped into blocks based on similar levels of that variable. This allows the effects of the extraneous variable to be isolated and minimized, improving the accuracy of the treatment comparison. The completely randomized design does not account for potential extraneous variables, the factorial design examines the effects of two or more independent variables simultaneously, and the interactive block design is not a commonly used experimental design.

In Which Experimental Design Is a Single, Categorical Extraneous Variable