Participants:

This design may be used for between-groups analyses and within-groups analyses.If each participant has only one score, then it is a between-groups design.In other words, each participant will only be contributing to one level of the design.For example, one IV might be study technique, with 10 students studying for an exam using technique A, 10 using technique B, and 10 using technique C.

If each participant has scores for each level, then it is a within-groups design.In this instance, the same 10 students would study for different exams using each of the 3 techniques.

Statistical power is usually determined before deciding how many participants must be recruited.Power depends on the effect size you predict; smaller effect sizes require more participants.For our purposes, we will say that there must be at least 10 participants per group; more participants per group is preferable if it is practical.

Different levels of the IV may have unequal numbers of participants, but the levels should not be too unequal.

Participants must be randomly assigned to groups.

Analysis:

Analysis of between-group designs uses ANOVA (ANalysis Of VAriance).Analysis of within-group designs uses One-Way Repeated Measures ANOVA.

If the result of ANOVA determines there is a statistically significant difference, post-hoc analyses must be conducted to determine which pairings of the levels in the IV are different.Typically, one will use the Tukey Test for Honestly Significant Differences.

If the result of ANOVA determines there is a statistically significant difference, it is common to calculate the effect size, or the amount of variability in the DV based on differences in the IV.This number will vary between 0.0 (no effect) and 1.0 (complete determination).Effect size is also called eta-squared (²).

Construct a research example for a design with more than 2 levels of an independent variable. The study should be a between-subjects design. what is the research question? What is the independent variable and the levels? What is the dependent variable? What is the H0? What is the H1? Who are the participants? Briefly describe the procedure.