Experimental Research Strategies

Question 1

What are the four basic elements of an experiment?

Answer 1

• Manipulation
• Measurement
• Comparison
• Control

Question 2

What are the two critical components of an experiment?

Answer 2

1) Independent vs Dependent variable
* More than one IV = factorial
* More than one DV = multivariate
2) Experimental vs Control group

Question 3

What are the two approaches to comparing group differences?

Answer 3

1) Between-subject design: each group gets a different treatment.
2) Within-subject design: Subjects get both treatment
levels.

Question 4

Advantages of between-subject design? (2)

Answer 4

1) Each measured score is independent.
2) Can be applied to wide range of research questions.

Question 5

Disadvantages of between-subject design? (2)

Answer 5

1) Need more individuals.
2) Individual differences can lead to differences between groups even before any manipulation has occurred

Question 6

What is variability?

Answer 6

Variability refers to the distribution of scores.

Question 7

Variability of between-subject design?

Answer 7

Differences between treatments. We want large variability.

Question 8

How to mitigate variance? (3)

Answer 8

Standardize procedures and treatment setting
Sample size (larger)
Group equivalency

Question 9

What are the types of between-subjects tests? (2)

Answer 9

Posttest-pretest
Matched pair

Question 10

What is the goal of posttest pretest?

Answer 10

The goal is to compare the treatment vs control group (not pre-test vs post-test)

Question 11

What are the pros of posttest pretest?

Answer 11

Pros:
* Test equivalence of groups
* Limit threats to internal validity

Question 12

What are the cons of posttest pretest?

Answer 12

Cons:
* Time-consuming
* Sensitize participants to procedure

Question 13

What is the matched pair design?

Answer 13

Each condition uses different participants but they are matched in terms of important characteristics.

Question 14

What are the pros of the matched pair design?

Answer 14

Pros:
* Minimize the effect of individual differences

Question 15

What are the cons of the matched pair design?

Answer 15

Cons:
*Attrition affects both groups
* If B1 drops out, B2 must be taken out also
* Difficult to match people exactly

Question 16

Within-subject design advantages? (2)

Answer 16

• Fewer participants are needed
• Eliminate variability due to individual differences

Question 17

Within-subject design disadvantages?

Answer 17

• Participant attrition
• Cannot apply this design to all studies
• Time-related effects (history (environmental), maturation, instrumentation, order, sequence)

Question 18

What is counterbalancing?

Answer 18

With counterbalancing, the participant sample is divided in half, with one half completing the two conditions in one order and the other half completing the conditions in the reverse order.

Question 19

The goal of counterbalancing?

Answer 19

Use every possible order of treatments with an equal
number of individuals participating in each sequence.

Question 20

What is a placebo?

Answer 20

People experiencing improvement in their condition even though they were assigned a dummy sugar pill without an active ingredients.