1. Single Factor – Two Levels: the simplest of all experimental designs; uses one IV which has two levels.
 

a. Between-Subjects, Single-Factor Designs – not very common; too simple

b. Within-Subjects, Single-Factor Designs – need to worry about counterbalancing:

• If subjects participate in each condition just once, COMPLETE counterbalancing will be used
• If subjects are tested more than once per condition:
• reverse counterbalancing will be used (ABBA)
• or we simply alternate the conditions (ABAB ...)

c. Analyzing Single-Factor, Two-Level Designs:

• t test for independent groups – (a) participants are randomly assigned to the groups or (b) the IV is a subject one (males vs. females)
• t test for dependent groups – within-subject design or matches groups.

2. Single Factor – More Than Two Levels: Most single-factor studies use three or more levels
 

a. Between-Subjects, Multilevel Designs -- A distinct advantage of multilevel designs is that they enable the researcher to discover NONLINEAR EFFECTS

b. Within-Subjects, Multilevel Designs – counterbalancing

c. Presenting the data

• Sentence (paragraph) form
• Table of results
• Graphs – bar graphs for nominal (discrete) data; line graphs for continuous data.

d. Analyzing Single-Factor, Multilevel Designs -- ANOVA