Variables
Definition
Key Features
Sample
Experiments
100

The factor that scientists purposefully change in an experiment, that is the “cause” in a “cause and effect” relationship.

What is a Independent Variable 

100

A way to gather information by having people answer a set of predetermined questions, to reveal information about attitudes, opinions, and beliefs. This cannot prove causation like an experiment can, but is more accessible to a wider audience.

What is a survey

100

Empiricism, which describes planning the method of observation and carefully sticking to it—data must be collected rigorously and systematically; empirical questions, which are defined as any questions that can be answered through systematic empiricism; and public knowledge, meaning that the results must be published or presented with others in some way, opening up the research for critique.

What are the key features of “Science”

100

A part of the population—the larger group that researchers want to learn about—that is selected to be studied and have drawn conclusions about. To be a good one of these, it is important that every item or person in the population has an equal chance of being selected, and are not selected because of convenience, or self-volunteering.

What is a sample

100

The group that the researchers want to learn more about, that can be (and often is) larger than what is reasonably able to be studied in an experiment, survey, or other research method.

What is a population

200

The factor that is not changed by scientists in an experiment, but may be affected by the other variable, that is the “effect” in a “cause and effect” relationship.

What is a dependent variable

200

A relationship between two variables where one directly affects the other. This has three requirements: covariation (there is a present relationship between the variables), a time-order relationship (the cause comes before the effect), and the elimination of any possible alternative causes.

What is causation

200

Activities or beliefs that may appear to be scientific—but are not— may be believed because of individual motivation, prior knowledge, or trust in the person or entity presenting the information.

What are the key features of Pseudoscience?

200

In this strategy of participant assignment to different groups, every subject has an equal chance of being selected for the study or a specific testing group. It is entirely random who is selected, on the individual level.

What is a simple random sample

200

A controlled environment where researchers change an independent variable, and observe the effects on a dependent variable. A pro of this answer is that, in some instances, they can demonstrate a cause and effect relationship between variables, which is not possible with a design such as correlational research. However, confounding variables can affect the results of the experiment, which is why random assignment on the individual level is needed.

What are experimental studies

300

An outside factor that may affect the independent and dependent variables, that researchers must control before causation can be determined between two correlated variables.

What are confounding variables

300

The relationship between two variables described on a scale from -1 (strong negative association) to 1 (strong positive association), with 0 meaning no association.

What is correlation

300

In this strategy of participant assignment to different groups, the population is first split into groups of similar people. Then, a random sampling is performed within each group to select the participants for the study. This ensures that the researchers will interact with people from each different group, which simple random sampling does not.

What is a stratified random sample?

300

In this type of experiment, participants are randomly assigned into certain variables in existing groups, rather than individually. Researchers need to control for possible confounding variables, because existing differences may occur in these groups, which could affect the results in a way that would not exist if participants were assigned individually.

What is quasi-experimental design