Pr. Fred Switzer
Lecture Notes – Research Methods
“Psychology is math that is applied to people.”
Nobody ever says “proof” in science – we say “evidence” because the game is never over
What’s a theory?
A theory is an explanation using an integrated set of principles that organizes and predicts
observations. They’re not right or wrong, proven or disproven, just statements.
What’s a hypothesis?
A testable prediction that is often implied by a theory, and is also known as a research question.
**Constructs = hypothesized psychological structures, mechanisms, and variables (Ex:
Introversion vs. Extroversion)
**Operational Definition = actually implementing or measuring a construct (whatever procedure
is used to measure the construct of question)
**Construct Validity = does the hypothesized construct actually exist? High or Low based on
how valid a construct is
What are variables?
These are constructs that can vary, or change. These are opposite of constants, constructs that
**Measurement = assigning numbers to a phenomenon such that the characteristics of the numbers
reflect the characteristics of the phenomenon
More Definitions related to Psychological Science:
**Population = the group of people you’re applying your conclusions to
**Sample = the group of people you’re actual studying
**External Validity = generalizability
**Internal Validity = can you trust your own conclusions? You need controls.
How to Conduct an Experiment:
1. Determine independent variable and vary it to determine cause and effect
2. Control other fac