Question

light and exam performance: a study is designed to test the effect of light level on exam performance of students. the researcher believes that light levels might have different effects depending on students visual acuity, so wants to make sure students with different visual acuity are equally represented in each treatment. the treatments are fluorescent overhead lighting, yellow overhead lighting, no overhead lighting (only desk lamps). what is the blocking variable? exam performance light level visual acuity

Explanation:

A blocking variable is a variable that is used to control for known sources of variability in an experiment. Here, the researcher believes light levels might affect exam - performance differently based on visual acuity and wants equal representation of students with different visual acuity in each treatment. So, visual acuity is used to create blocks.

Answer:

Visual Acuity