Independence of Main Effects

Example of a Main Effect

Simple Effect

Interaction Effect

In a factorial design, which of the following best describes a main effect?

A researcher conducts a factorial study to see how 'Room Lighting' (Dim vs. Bright) and 'Music Type' (Classical vs. Rock) affect 'Reading Speed'. Match the following descriptions to the corresponding concepts of main effects.

A researcher conducts a study to examine how 'Exercise' (None vs. Regular) and 'Diet' (Standard vs. Specialized) affect weight loss. The mean weight loss results for each condition are:

• None / Standard: 2 lbs
• None / Specialized: 6 lbs
• Regular / Standard: 6 lbs
• Regular / Specialized: 2 lbs

True or False: These results show a main effect of Exercise.

A researcher is reviewing data from a study with two independent variables to determine if the first variable has a consistent overall impact on the results. Arrange the steps of the evaluative process in the correct logical order, from the initial setup to the final judgment of a main effect.

Match each research concept to its correct definition within the context of factorial designs.

In a factorial design evaluating the impact of 'Lighting' (Dim vs. Bright) and 'Room Temperature' (Cool vs. Warm) on 'Test Performance,' a researcher calculates the main effect of 'Lighting.' Which of the following best explains what this main effect represents?

A researcher is analyzing the main effect of 'Study Method' in a factorial design. The marginal mean for the 'Visual' group is $85$. For the 'Auditory' group, the cell mean in the 'High Motivation' condition is $80$. If the researcher determines there is no main effect of Study Method, the cell mean for the 'Auditory' group in the 'Low Motivation' condition must be _____.

A researcher conducts an experiment with three independent variables: 'Feedback Type' (positive vs. negative), 'Task Difficulty' (easy vs. hard), and 'Time Limit' (strict vs. generous). In this factorial design, there are exactly three potential main effects to evaluate.

In a factorial design, the main effect of a single independent variable is determined by averaging the results across all levels of the _____ independent variables.

Order the steps a researcher would take to isolate and evaluate the main effect of a specific independent variable in a factorial design.