This document discusses two types of independent variables: independent samples and repeated samples. Independent samples involve groups that are completely separate from each other, like singles and married people. Repeated samples involve the same group being measured more than once, like students taking a pre-test and post-test for a course. Marital status is an example of an independent variable with independent samples, while time is an independent variable with repeated samples as a group of students is tested before and after a course.

1. Independent samples are samples from groups that are completely separate
from one another.
A repeated sample is the same group measured more than once
Marital Status
TWO Levels Single Married
Independent Variable
Independent Samples One cannot be single and married at the same
time; therefore, a sample of singles and a sample
of marrieds are independent from one another.
Time
TWO Levels Pre-test Post-test
Independent Variable
Repeated Samples
A group of students are tested at the beginning of
the course and then tested AGAIN at the end of
the course and thus are considered repeated
samples.