Ch7: The Experimental Research Strategy

Question 1

What is the goal of experimental research strategy?

Answer 1

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

Question 2

Four basic elements of a true experiment:

Answer 2

1. Manipulation
2. Measurement
3. Comparison
4. Control

Question 3

The variable that is measured is called the ___ ___ and that which is manipulated is the ____ ____

Answer 3

The variable that is measured is called the DEPENDENT VARIABLE and that which is manipulated is the INDEPENDENT VARIABLE

Question 4

What does a true experiment try to show?

Answer 4

that changes in one variable are directly responsible for the changes in a second variable

Question 5

Third-variable problem

Answer 5

Although a study may establish that two variables are related, it does not necessarily mean that there is a direct (causal) relationship between the two variables.
It is possible that a THIRD (unidentified) VARIABLE is controlling the two variables and responsible for producing the observed relation

Question 6

alternative methods to hypothesis testing?

Answer 6

• Cohen’s d
• R squared
• Confidence intervals

Question 7

3 conditions for determining cause and effect:

Answer 7

• covariation of cause and effect
• temporal precedence (directionality problem)
• alternative explanations (third variable problem)

Question 8

Directionality problem

Answer 8

Although a research study may find a relationship between two variables, this does not explain the direction of the relationship. Problem is to determine which variable is the cause and which is the effect.
e.g., does aggressive cause a kid to play more violent video games, or do violent video games cause aggressive behaviour?

Question 9

Two elements that are unique only to experimental research strategies

Answer 9

• control of extraneous variables

- manipulation of one variable

Question 10

Researcher observed that people who suffer from eating disorders tend to have low self-esteem. He’s not sure whether the self-esteem leads to an eating disorder or whether having an eating disorder leads to low self-esteem. This is an example of what problem?

Answer 10

directionality problem

Question 11

Researcher is interested in how a new drug impacts symptoms of depression. Name 3 ways they could test the effectiveness of the drug.

Answer 11

3 WAYS TO MANIPULATE THE IV:

1. Different levels of treatment: 2 groups receive diff. dosage levels.
2. Different treatment categories: one group receives new treatment, the other receives existing treatment.
3. Treatment vs no treatment: one group receives drug, one group does not.

Question 12

Researchers interested in the effect of alcohol consumption on socializing carefully control the amount of alcohol they allow participants to consume and observe the number of people each participant speaks to. What kind of manipulation is being employed?

Answer 12

Different levels of treatment/IV

Question 13

Which necessary condition of causality does manipulation in an experiment help?

Answer 13

• temporal precedence/directionality.

- by manipulating one variable, experimenter is ensuring directional/temporal precedence.

Question 14

In general, whenever there is a relationship between two variables, a researcher can use manipulation to determine which variable is the ___ and which is the ____

Answer 14

cause and effect

Question 15

What is a manipulation check?

Answer 15

an additional measure to assess how the participants perceived and interpreted the manipulation and/or to assess the direct effect of the manipulation.
It directly measures whether the IV had the intended effect on the participant.

Question 16

Which necessary condition of causality does experimental control help?

Answer 16

helps rule out ALTERNATIVE EXPLANATIONS

Question 17

What kinds of variables need to be controlled for in an experiment?

Answer 17

CONFOUNDING variables

Question 18

All individuals in an experiment are observed in the same room, at the same time of day, by the same researcher. What method is this an example of?

Answer 18

• a method of CONTROLLING EXTRANEOUS VARIABLES by HOLDING A VARIABLE CONSTANT.
• this eliminates extraneous variables by holding them constant

Question 19

In an experiment, participants are assigned so that the average age is the same for all the different treatment conditions. This is an example of what method of control?

Answer 19

MATCHING values across treatment conditions.

-in this case, age is balanced across treatments and, therefore, cannot be a confounding variable

Question 20

2 benefits of random assignment

Answer 20

• as sample size gets larger, the differences between the groups become smaller
  2. even if there are differences, they aren’t systematic

Question 21

the use of a random process to help avoid systematic relationship between two variables is called ___

Answer 21

randomization

Question 22

A researcher’s schedule requires some observations in the morning and some in the afternoon. How can he control for environmental variables?

Answer 22

he could toss a coin each day to determine whether treatment I or treatment II is to be administered in the morning. In this way, morning hour is equally likely to be assigned to treatment condition I or II.
Thus, time of day is randomly distributed across treatments and does not have a systematic effect on the outcome.
RANDOMIZATION technique

Question 23

Holding a variable constant has the disadvantage of limiting _____

Answer 23

generalization (external validity)

Question 24

When a drug with no medical effect is administered and the participant still shows a response, this is called ___ ___

Answer 24

placebo effect

Question 25

In an experiment, a _____ ____ ____ is a condition in which the participants do not receive the treatment being evaluated

Answer 25

no-treatment control group

Question 26

A ___ ___ ___ is a condition in which participants receive a placebo instead of an actual treatment

Answer 26

placebo control group

Question 27

4 methods of experimental control

Answer 27

1. random assignment
2. holding constant
3. matching
4. control conditions

Question 28

In a ____-____ ____, each participant is exposed to all levels of the IV, while in a ___-____ ____, each participant is only exposed to one level of the IV

Answer 28

In a WITHIN-SUBJECTS DESIGN, each participant is exposed to all levels of the IV, while in a BETWEEN-SUBJECTS DESIGN, each participant is only exposed to one level of the IV