This document describes a 2x2 factorial experimental design to study the effects of teaching method and aptitude on student performance. The study will randomly assign 3rd graders scoring below or above 85 on an aptitude test to either a lecture only or lecture with small group discussion teaching method. This creates four groups to examine the influence of two independent variables - teaching method and aptitude level - on the dependent variable of student performance.

1. Experimental Design
Factorial Design
Diagram
Independent Variable #1:Teaching Method
Independent
Variable #2:
Aptitude
Randomly assigned 3rd
graders scoring below 60 on
an aptitude test.
Randomly assigned 3rd
graders scoring below 60 on
an aptitude test.
Randomly assigned 3rd
graders scoring about 85 on
an aptitude test.
Randomly assigned 3rd
graders scoring above 85 on
an aptitude test.
Reading/Lecture/Etc.
Lecture Only
High
Low

2. Experimental Design
Factorial
Independent Variable #1 Teaching Method
How many possible Teaching Methods are there? Which will
be the methods used in the study? If more than one will be
used, each method may be considered a factor of the
variable known as Teaching Method.
Teaching Method
Lecture only
Lecture & Small
Group Discussion

3. Experimental Design
Factorial
Independent Variable #2 Aptitude
How many possible levels of aptitude are there? How many
may be represented in the group of subjects participating in
the study? Once identified, levels of aptitude may be
considered factors of the variable known as Aptitude.
Low
High
Aptitude

4. Experimental Design
Factorial
Lecture only
Lecture & Small
Group Discussion
Low High