Lesson 5 - Causal Research & Experimental Design

Question 1

Conditions for causality

Answer 1

1. Time Order ( x cannot happen after y)
2. Elimination of other possible causes (holidays)
3. Covariation (y must co-vary with x)

Question 2

Correlation

Answer 2

Is not causation

Question 3

Example correlation ❌ causation

Answer 3

Ice cream sales and shark attacks are correlated because they occur on the same time but there is no causation because there is no covariation between them and there is no evidence that they co-vary

Question 4

What happens at correlation

Answer 4

X and y can change together

Question 5

What happens at causation

Answer 5

Changing x causes a change in y

Question 6

What is an experiment?

Answer 6

• primary method of establishing a cause-and-effect relationship
• used for testing specific hypotheses

Question 7

Steps of an experiment

Answer 7

1. Divide participants into two or more groups ( control and experimental group)
2. Expose each group to different treatments
3. Measure the outcomes of each group
4. Compare outcomes for differences

Question 8

Example experiment Coke

Answer 8

• 2 groups
• control group: small thick can of coke
• experimental group: tall skinny can
• ask them which can has more coke in it
• people think tall thin ones have more coke in it and they drink it slower than the others

Question 9

Basic definitions and concepts of experiments

Answer 9

• independent variable
• dependent variable
• experiment

Question 10

Independent variable

Answer 10

• predictor variables
• variables that are manipulated by researcher
• ex package design

Question 11

Dependent variable

Answer 11

• outcome variable
• variables that measure the effect of manipulating the independent variables
• ex. sales

Question 12

Definition Experiment

Answer 12

Process of manipulating independent variables and determining their effect on dependent variables

Question 13

Example experiment 2

Answer 13

Will students score be affected by distracting sounds in the environment?
Control group: takes the test normal
Experimental group: has a band in the room while taking the test

Question 14

Example experiment 3

Answer 14

Manager wants to find out whether in-store phone use affects purchase
Independent variables: phone use
Dependent variable: total purchases

Question 15

Field experiments

Answer 15

Conducted in natural setting where realism is higher

Question 16

Lab experiments

Answer 16

Conducted in lab where extraneous variables can be controlled

Question 17

Pro-Contra lab studies

Answer 17

• high internal validity
• controlled environment
  Pro: stronger ability to establish causality
  Contra: low generalizability

Question 18

Pro-Contra field experiments

Answer 18

• high external validity
• real-world environment
  Pro: natural responses are obtained
  Contra: difficult to control, expensive

Question 19

Extraneous variables

Answer 19

Any variable that you are not investigating that can potentially affect the outcomes of your research (ex. Black Friday)

Question 20

Goal experiments (picture)

Answer 20

Manipulate:
Independent variable
(Phone use) \

                             Dependent variable
                                (Consumption)

Extraneous variables /
z (Black Friday)

Question 21

Threats to validity

Answer 21

Extraneous variables

Question 22

Types of extraneous variables

Answer 22

• history
• maturation
• mortality
• instrument variation
• selection bias
• testing effects
• demand effects
• regression to mean

Question 23

Extraneous variable history

Answer 23

Events or actions during experiment that may influence dependent variable

Question 24

Extraneous variable maturation

Answer 24

Change in participants during experiment that may influence response to treatment

Question 25

Extraneous variable mortality

Answer 25

Drop-out of participants during experiment

Question 26

Extraneous variable instrument variation

Answer 26

Change in measurement instruments that may effect measurements

Question 27

Extraneous variable selection bias

Answer 27

Biased participant selection that drives differences between test and control group

Question 28

Extraneous variable testing effects

Answer 28

Mere deft of earlier responses on later responses

Question 29

Extraneous variable demand effects

Answer 29

Effect of participants guessing your hypothesis on behavior because there trying to help you find results

Question 30

Extraneous variable regression to mean

Answer 30

Tendency to move toward average response

Question 31

Types of experimental designs

Answer 31

• pre-experimental
• true experimental
• quasi-experimental
  -statistical

Question 32

Experimental designs pre-experimental

Answer 32

Either a single group or multiple groups are observed subsequent to some treatment presumed to cause change
Single case is observed at 2 time points, one before the treatment and one after. Changes in outcome are presumed to be result of intervention or treatment
-> one-group-pretest-post-test

Question 33

Experimental designs true experimental

Answer 33

Participants are randomly assigned to either the experimental or control group
Selection bias is eliminated by randomization

Question 34

Experimental design quasi experiment

Answer 34

There is no randomization of test units to treatments
You hypothesize that a new after-school program will lead to higher grades

Question 35

Ethicality of experimentation

Answer 35

• responsibility to protect participants from harm
• respect rights and dignity of participants
• ethical guidelines

Question 36

Limitation of experimentation

Answer 36

• experiments can be time consuming especially during long term experiments
• expensive because control, experimental group and multiple measurements
• it may be impossible to control effect of extraneous variables (especially in field experiment)

Question 37

Research designs

Answer 37

Exploratory research design
(Qualitative)
⬅️➡️
Conclusive research design
(Quantitative)
⤵️
Descriptive research
Causal research