Participants respond to an ad or posting and elect to be in the research
Volunteer/Self-selected
An educated guess/prediction about the relationship between the IV and the DV
Hypothesis
Data that is based on personal experience; subject to bias
Anecdotal
Participants are chosen because they are easy to access and available
Opportunity/Convenience
The measured variable
Dependent Variable
Data that is numerical, observable, measurable
Empirical
Participants all have an equal chance of being selected. For example, pulling names from a hat
Random
The manipulated/changed variable
Independent variable
This occurs when selected participants are not representative of the target population
Selection Bias
When participants recruit other participants from among their friends, coworkers, and acquaintances
Snowball
Description of how a variable is measured
Operational definition
The group that a psychologist is trying to draw a sample from is called:
Target Population
The target population is divided into subgroups based on a common characteristic (age, race, gender, etc.) and are then randomly selected from those categories in proportion to their presence in the target population
Stratified
A factor other than the independent variable that might produce an effect in an experiment
Confounding Variable
When a sample is an accurate picture of the group you are trying to study it is:
Representative/Generalizable