True Experiment

Question 1

What is the goal of the experimental research strategy?

Answer 1

To establish the existence of a cause and effect relationship between two variables

This is the only research strategy that allows you to determine a causal relationship

Question 2

What does a “true” experiment demonstrate?

Answer 2

A “True” Experiment demonstrates that changes in one variable are directly responsible for causing changes in the second variable

Question 3

What are the four required elements of a “true” experiment?

Answer 3

1. Manipulation
   - Researcher manipulates one variable by changing its value to create a set of two or more treatment conditions
2. Measurement
   - A second variable is measured for a group of participants resulting in a set of scores in each treatment condition
3. Comparison
   - The scores in one treatment condition are compared with the scores in another treatment condition
4. Control
   All other variables are controlled to be sure that they do not influence the two variables being examined

Question 3

What is the independent variable?

Answer 3

The variable that is manipulated by the researcher by creating a set of treatment conditions: the cause

• Treatment condition: a situation or environment characterized by one specific
  value of the manipulated variable (Experimental vs. Control Condition)
• Levels: different values of the IV selected to create and define the treatment
  conditions (Drug vs. Placebo)

Question 4

What is the dependent variable?

Answer 4

The variable that is observed for changes to assess the effects of manipulating the IV; the effect

Question 5

What are extraneous variables?

Answer 5

All other variables in the study other than the IVs and DVs

Question 6

What does manipulation refer to?

Answer 6

Refers to the deliberate change or variation of an independent variable by the researcher to examine its effect on the dependent variable

The researcher systematically alters the IV while keeping other variables the same
- I.e. Drug vs. Placebo: The experience of the patient is the same regardless of
whether they are getting the actual drug or the sugar pill

Question 7

Why is manipulation essential?

Answer 7

This is essential because it allows for causal inferences: determining whether changes in the IV, specifically, cause changes in the DV

Question 8

What does control refer to ?

Answer 8

In an experiment, control refers to the methods researchers use to determine the effect of the independent variable (IV) on the dependent variable (DV) while simultaneously minimizing the influence of extraneous variables

Proper control ensures that observed changes in the DV are due to the
manipulation of the IV rather than other confounding factors

Question 9

What is the control group?

Answer 9

A group that does not receive the experimental treatment, allowing comparison with the experimental group

Question 10

What is random assignment?

Answer 10

Participants are randomly assigned to different conditions to reduce selection bias

Question 11

What is holding variables constant or matching?

Answer 11

Keeping environmental factors, instructions, and procedures the same across conditions

Question 12

What are the pros and cons of control groups?

Answer 12

Pros
- Establishes causality
- Enhances internal validity

Cons
- Ethical concerns
- Resource intensive

Question 13

What are the pros and cons of randomization?

Answer 13

Pros
- Controls a wide variety of variables simultaneously

Cons
Is not guaranteed to be successful in balancing variables

Question 14

What are the pros and cons of holding constant and matching variables?

Answer 14

Pros
- Ensures that the variable is not influencing changes in your DV

Cons
- Require extra effort or extra measurement
- Limits external validity

Question 15

What is statistical significance?

Answer 15

The difference is large enough and consistent enough for a hypothesis test to rule out chance as a plausible explanation

• Therefore, the difference must have been caused by the treatments