Causal Research

Question 1

Types of Experiments

Answer 1

Laboratory Experiment

Field Experiment

Question 2

What is a Laboratory Experiment?

Answer 2

Created Situation
Independent variables are manipulated
Other variables can be perfectly controlled

Question 3

What is a field experiment?

Answer 3

Realistic situation
Independent variables are manipulated
Other variables are as perfectly controlled as the situation permits

Question 4

What is an experiment in general?

Answer 4

Controlled manipulation of one or more independent variables

Observation of variation in the dependent variable

Question 5

Experimental designs

Answer 5

Pre- experimental designs
True experimental designs
Quasi experimental designs

Question 6

2 Pre- experimental designs

Answer 6

1. Pre test - post test

2. Static group comparison

Question 7

2 True experimental designs

Answer 7

1. Before - After with CG

2. After only with CG

Question 8

1 Quasi experimental design

Answer 8

Time-series experiment

Question 9

3 forms of validity

Answer 9

Content validity
Construct validity
Criterion validity

Question 10

What is content validity?

Answer 10

Does a variable reflect what you want to measure?

-> Can be measured before the measurement

Question 11

What is construct validity?

Answer 11

• Convergent validity: Are the items of the same variable strongly related to one another?
• Discriminant validity: Are the items of a variable unrelated to different constructs?

Question 12

What is criterion validity?

Answer 12

Does a variable relate to others as predicted by theory?

Test relationship with theoretically connected variables

Question 13

Reliability: Methods to determine the convergent validity at the level of item:

Answer 13

Item-to-total correlation r^2

Correlation of every singe item with the average of all items

Question 14

Reliability: Methods to determine the convergent validity at the construct level

Answer 14

Cronbachs Alpha

Average of all correlations

Question 15

Steps of Hypothesis testing

Answer 15

1. Formulate Hypothesis
2. Select an appropriate test and check assumptions
3. Choose the significance level
4. Calculate the test statistic
5. Compare the test statistic (-value) with the critical value
6. Interpret the results

Question 16

Definition of Statistical Power

Answer 16

SP is the probability of rejecting the null hypothesis when it is in fact false (-> not making a type II error). Defined by 1-beta

Question 17

What is the effect size

Answer 17

The difference between the assumed value under the null hypothesis and the (true) unknown value