Chapter 8

Question 1

True experimental designs

Answer 1

experimental control: keeping all extraneous variables constant
randomization: making sure the experimental and control groups are equal at the start of the experiment

Question 2

Basic Experiments

Answer 2

• manipulate the independent variable at at least 2 levels (experimental group and control group)
  measure effect on dependent variable

Question 3

Post Test- only design

Answer 3

Recruit participants randomly, assign to experimental and control groups. Manipulate IU, measure effect on DU for each group
- any difference should be due to the IU
- random assignment eliminates selection difference many personal characteristics

Question 4

Pretest- PostTest Design

Answer 4

• same as pretest only design but includes a pretest- before the IV manipulation
• ensures that the groups were in foot equivalent at the start

Question 5

Pros of Pretests

Answer 5

Pretest- is a good idea with small sample sizes
- pretest- enables us to see change after IV, including for individual participants
- especially important for some participants drop out after the start of the experiment (called attraction or mortality)

Question 6

Pros of Pretests

Answer 6

pretest- is good with small sample tests
pretest- enables to see change after IV, including for individual participants
- especially important if some participants drop out after the start of the experiment (called attraction or mortality)

Question 7

cons of the pretests

Answer 7

• In real world usually no pretest- so having one may reduce external validty
• may be time consuming
• may give away the topic of your experiment

Question 8

Assigning participants to experimental conditions

Answer 8

• 2 basic options
• random assignment
  
  • called an independent groups design or between- subjects design
• Use same group of participants in both/all conditions
  
  • called a repeated measures design or within subjects design

Question 9

Characteristics of Repeated Measures Design

Answer 9

• each participant is their own control/comparison
• need fewer participants since you get to use them twice
• easier to find statistically sificant differences because can compare each person to him/herself
• need to watch out for order effects where the previous condition affects the next one
  0 deal with this prob either by delaying between conditions or by counterbalancing the order in which conditions are presented

Question 10

Order effects

Answer 10

• Practice effect: someone might perform better on the second condition because of experience on the first
• Fatigue effect: someone might do worse on the second condition because they’re tired from the first
• carryover effect: the intervention from the first condition might still be affecting someone when they do the second

Question 11

Complete Counterbalancing

Answer 11

all possible orders for conditions
- Latin square: a limited set of order that ensures that 1) each condition goes first, and last, and all the other positions, the same number of times, and 2) each condition precedes and follows each other conditionce

Question 12

Matched Pairs Design

Answer 12

• instead of randomly assigning participants to groups, match them into pairs a relevant variable, and randomly assign one person in each pair to experimental or control group
• helps ensure the groups one equivalent, at least on the match variable
• most important with a small sample

Question 13

Solomon four group design

Answer 13

Half participants recieve pretest and post test other half recieve only post test

• if there is no impact of pretest, the PostTest scores will be the same in the two control groups and expieremental groups

Question 14

Post test only design

Answer 14

A true experimental design in which the dependent variable (PostTest) is m/ only once. after manipulation of the iv

Question 15

Pretest- PostTest design

Answer 15

A true experimental design in which the dependent variable is measured both before (pretest) and after (PostTest) manipulation of the iv)

Question 16

Solomon Four Group design

Answer 16

experimental design in which the experimental and control groups are studied with a ND without a pretest

Question 17

Between Subjects Design

Answer 17

An experiment in which different subjects are assigned to each group. Also called independent groups design

Question 18

Within Subjects Design

Answer 18

An experiment in which the same subjects are assigned to each group

Question 19

Matched Pairs design

Answer 19

A method of assigning subjects to groups in which pairs of subjects are first matched on some Characteristic and then individually assigned randomly to groups

Question 20

Mixed design

Answer 20

A mixed subjects design, also known as a mixed design, is a research design that combines elements of both a within-subjects design and a between-subjects design.

Question 21

Between subjects design

Answer 21

A between-subjects experimental design is a type of design where participants are split into two or more groups and each group is assigned a treatment condition. These treatments are then compared to the other groups to see differences in the outcome of the experiment.

Question 22

within subjects design

Answer 22

A within-subjects design is a research method that involves testing the same group of participants under multiple conditions or over time. It’s also known as a repeated measures design or dependent groups design.

Question 23

dependent groups design

Answer 23

A “dependent groups design,” also known as a “within-subjects design” or “repeated measures design,” is a research design where every participant experiences all conditions of the independent variable

Question 24

repeated measures design

Answer 24

A repeated measures design is a research method that involves measuring the same variable on the same subjects multiple times.

Question 25

Describe an example of an experiment where variables are confounded in a way that makes the results difficult to interpret

Answer 25

Perhaps an experiment where that measures the relationship between age and nostalgia, however cohort groups are used and it is unclear whether or not the relationship is actually due to nostalgia or due to the culture being generally more nostalgic in past years than currently.

Question 26

What is the purpose of random assignment? What happens if you don’t do it?

Answer 26

Random assignment ensures equality in groups
- no bias possible

Question 27

Describe the difference between an independent groups design and a repeated measures design, using examples.

Answer 27

Independent variable are where different people try the group
Repeated measures are when the same people try the experiment multiple times

Question 28

Explain how practice, fatigue, and carryover effects can interfere with results in a repeated measures design. Use examples.

Answer 28

Practice effects: people learn and get better at the experiment
Carryover effect: people are in a similar mindset to the last topic
Fatigue effect: people get tired and do worse on each effect

Question 29

Using an example, describe how counterbalancing is used to control for possible order effects in an experiment.

Answer 29

Counterbalancing can get rid of practice, fatigue, and carryover effects by randomizing the condition order to cancel them out

Question 30

Describe the procedure for conducting a matched pairs design, and explain why you would do this.

Answer 30

People in the control group and experimental group are matched and their means compared