module 9

Question 1

Experiment

Answer 1

in an experiment researchers manipulate at least one variable and measure at least one other variable

Question 2

Lab experiment

Answer 2

Experiment in artificial environment

Question 3

Field experiments

Answer 3

Experiment in a natural setting

Everyday real life environment of participant

–> setting participants manipulators and outcome measures are authentic

Question 4

example difference field experimental

Answer 4

Suppose you would like to know whether running a large ad on Google is more effective than running a small ad. Put differently, is it worth the money to run a large ad? You could opt for a lab experiment and invite people to the lab, where you ask them to imagine that they are searching Google. You show half of them a Google page (fabricated by you) with a small ad, and the other half of them a Google page with a large ad (also fabricated by you). Afterwards, you ask all participants to fill out a small questionnaire comprising, amongst others, a question on whether or not they would be inclined to click on the ad they just saw.

Alternatively, you could run a field experiment in which you manipulate ad size on an actual Google page, with half of the Google page visitors seeing the large ad and the other half the small ad. You could then measure the number of people that click on the ads.

The field experiment has:

an authentic context: an actual Google search (rather than having people imagine that they are searching Google);
authentic participants: people who genuinely search on Google (rather than people who may never search Google but are now instructed to do so)
authentic treatments: real ads (rather than fabricated ads)
authentic outcome measures: actual click rates (rather than asking people whether they would be inclined to click on the ad if they were in the real world)

Question 5

Experiments (lab or field) are particularly suitable when

Answer 5

The number of independent (and moderator) variables is limited and

At least one independent variable can be manipulated

Question 6

When is a lab experiment preferred over a field experiment

Answer 6

When researchers want maximum control over the research environment to rule out alternative explanations

Question 7

When is a field experiment preferable over a lab experiment

Answer 7

When it is essential to measure real-world behavior in real-world situations i.e. when high external validity is crucial. After running a lab experiment, researchers can only speculate to what extent their findings would apply to a real-world setting. After running a field experiment, they know their findings apply to a real world setting

Question 8

The levels of the manipulated variable are referred to as

Answer 8

Conditions

Question 9

control group

Answer 9

A level of the independent variable that represents a neutral condition. When a study has acontrol group, the other levels of the variables are called the treatment groups

Question 10

between subject experiment design

Answer 10

Different groups of subjects are assigned to different levels of the independent variable

Question 11

within subject experiment design

Answer 11

Each subject (participant) is presented with all levels of the independent variable

Question 12

Posttest only experiment design

Answer 12

Simplest between subject design

Subjects are randomly assigned to the levels of the independent variable

The dependent variable is then measured once

Question 13

Pretest/posttest experiment design

Answer 13

Subjects are randomly assigned to the levels of an independent variable

The dependent variable is measured twice: once before and once after exposure to the independent variable

Question 14

Pretest/posttest experiment design

Answer 14

Subjects are randomly assigned to the levels of an independent variable

The dependent variable is measured twice: once before and once after exposure to the independent variable

Question 15

Why would researchers use a posttest only design, why not always use a pretest/posttest design?

Answer 15

Sometimes it may be problematic to measure the dependent variable beforehand, as it may influence the second measurement. IF the pretest makes participants change their subsequent behavior/reaction, a pretest should be avoided

Question 16

Interaction or moderator effect

Answer 16

Whether the effect of one independent variable depends on the level of the other independent variable

Question 17

Factorial research:

Answer 17

Combine the two independent variables: they study each possible combination of the independent variables

Question 18

Factorial dsign

Answer 18

design with more than one IV

Test for interaction / moderation effects

Question 19

Illustration: factorial design:

Answer 19

Hypothesis:
Tag ons increase recall, but have a negative effect on attitude (boredom and or irritation)

The negative effect of tag-ons can be prevented by varying the tag-on

Experimental design:

IV1: tag-ons
IV2: variation
DV: Attitude towards ad

Question 20

In a within subjects factorial design, both independent variables are manipulated as

Answer 20

Within subjects. Therefore if the design is a 2x2 design, there is only one group of subjects in the experiment but they participate in all four cells (or combinations) of the design

Question 21

In mixed factorial designs, one independent variable is manipulated as

Answer 21

Between subjects and one independent variable is manipulated as within subjects

Question 22

The notation for a factorial design with two independent variables is “a x b”, where:

Answer 22

a indicates the number of levels of the first independent variable

B indicates the number of levels of the second independent variable

An example:

A 3x4 factorial design has two independent variables, one with three levels and one with four levels. It results in 12 cells (3x4 = 12).

Question 23

Sometimes, research studies have three independent variables. Such a design is called a three-way design. For example, in a 2x2x2 factorial design, there are two levels of the first independent variable, two levels of the second independent variable, and two levels of the third independent variable.

This leads to how many cells or condition in the experiment?

Answer 23

eight cells or conditions in the experiment (2x2x2 = 8).

Three way factorial designs are complex to interpret. A three-way interaction means that the two-way interaction between two of the independent variables depends on the level of the third independent variable

Question 24

Concrete measure of dependent variable

Answer 24

E.g. the number of M&Ms eaten

Question 25

abstract measurement of dependent variable

Answer 25

E.g. the perceived tastiness of an M&M

Question 26

Level at which chronbachs alpha is acceptable

Answer 26

> 0.70

–> items in a measurement instrument are internally consistent

Question 27

The validity of measured variables (such as the dependent variable in an experiment) can be demonstrated by:

Answer 27

Providing precedence (has this measure been used before?)

Using sound logic (why does this measure capture the variable?)

Question 28

The validity of manipulated variables can be demonstrated by

Answer 28

Providing precedence (has this manipulation been used before?)

Using sound logic (why does this manipulation capture the variable?)

Manipulation checks

Question 29

The validity of manipulated variables can be demonstrated by

Answer 29

Providing precedence (has this manipulation been used before?)

Using sound logic (why does this manipulation capture the variable?)

Manipulation checks

Question 30

Manipulation check

Answer 30

Is a test used to determine the effectiveness of a manipulation in an experimental design. It is used to ensure that the participants understood the manipulation the way the researcher intended

Question 31

internal validity refers to

Answer 31

The ability to draw valid conclusions about the causal effects of the independent variables on the dependent variable. Internal validity can be threatened in a variety of ways in experiments

Question 32

Experimenter bias

Answer 32

Experimenter bias occurs when the experimenter (intentionally or unintentionally) affects data, participants or results in an experiment because he is unable to remain objective. Most modern experiments are designed in a way to reduce the possibility of bias-distored results. In general, biases can be kept to a minimum if experimenters are properly trained and clear rules and procedures are put in place for the experiment

Question 33

Steps can be taken to reduce the likelihood of its occurrence such as

Experimentor bias

Answer 33

Conducting blind studies and minimizing exposure to experiments

Question 34

In a blind study:

Answer 34

All the information which may influence the outcome of the experiment is withheld from the experimenters and the participants (e.g. when participants are unaware of the hypothesis, they will not be able to influence the outcome of the experiment)

Question 35

The less exposure respondents have to experimeters

Answer 35

The less likely it is that they will pick up any cues that would impact their answers. One of the common ways to minimize the interaction between participants and experimenters is to prerecord the instructions

Question 36

History effect:

Answer 36

Events/ factors outside the experiment have an impact on the DV during the experiment

Question 37

Maturation effect:

Answer 37

Biological/phychological changes over time

Question 38

Testing effect:

Answer 38

Prior testing affects the DV

Question 39

Threats to internal validity:

Answer 39

History effect

Maturation effect

Testing effect

Instrumentation effect

Selection bias effect

Mortality effect

Question 40

Instrumentation effect

Answer 40

The observed effect is due to a change in measurement

Question 41

selection bias effect

Answer 41

Incorrect selection of respondents (experimental and/or control grouup)

Question 42

Mortality effect:

Answer 42

Drop out of respondents during experiment

Question 43

Increasing internal validity: controlling for extraneous variables

Answer 43

Randomization

Design control

Statistical control

Question 44

Randomization:

Answer 44

Random allocation of participants to different conditions (selection bias, but also instrumentation, history, ortality)

Question 45

Design control:
Control group

Answer 45

Include group that does not receive the treatment (history and maturation, but also instrumentation, and statistical regression.)

Question 46

Design control:
Extra groups:

Answer 46

Groups without pre-test but with an experimental manipulation to exclude the effects of pre testing

Question 47

Statistical control

Answer 47

Measure extraneous variables and include these in the statistical analysis (covariance analytics)

Question 48

Can findings from the lab experiment be generalized directly to real jobs?

Answer 48

No the types of participants that participate in the lab experiment may be (and typically are) very different from the population of interest. For example, university students might be assigned an artificial task in a lab experiment to study the effect of receiving bonuses on their work performance

Question 49

To conduct a clean confound-free manipulation (high internal validity) researchars may have to

Answer 49

Conduct their study in an artificial environment, like a university laboratory, which is not representative of the real world

Question 50

Internal validity of lab experiments is typically

Answer 50

High

Question 51

External validity of lab experiments is typically

Answer 51

Low

Question 52

Random sampling

Answer 52

Is the random selection of subjects from a population. It, therefore, pertains to the studys external validity

Question 53

Random assignemnt

Answer 53

Is about randomly assigning each subject in the sample to the experimental conditions. It therefore pertains to the studys internal validity