,Contents
Summary of the IRM short guide.........................................................................................3
1. Research Questions and Research Types................................................................................ 4
2. Conceptualization and Hypothesis Formulation......................................................................4
3. Operationalization and Data Collection.................................................................................. 4
4. Data Analysis with Cross-Tabulations (Crosstabs)................................................................... 5
5. The Elaboration Model...........................................................................................................5
6. Trivariate Analysis: Why It Matters.........................................................................................7
R specific codes................................................................................................................... 7
R specific codes for unit 4...........................................................................................................7
o Load a package....................................................................................................7
- View the dataset.................................................................................................. 7
- If you are interested in just one variable of the dataset,........................................7
- explore a variable in your dataset......................................................................... 7
- Load a CSV file..................................................................................................... 7
current working directory......................................................................................... 7
- If you want to find the variables in the data file,.................................................... 7
- Create a new dataset with only two variables from the dataset............................ 8
- How to filter in a dataset:.......................................................................................8
- How to clean the global environment.................................................................... 8
R specific codes for unit 7................................................................................................... 8
R specific codes for unit 9...........................................................................................................8
- How to make a frequency table.............................................................................8
- How to make a histogram..................................................................................... 8
- Change bin width.................................................................................................. 8
- Recoding a variable (mutate)................................................................................ 9
- How to make frequency tables..............................................................................9
- How to make bar charts........................................................................................ 9
R specific codes for unit 11.......................................................................................................10
- Compute the mean..............................................................................................10
- Compute the standard deviation......................................................................... 10
- Computer the variance........................................................................................10
- How to make a boxplot........................................................................................10
- How to use multiple variables into one boxplot................................................... 10
Standardizing Variables......................................................................................10
R specific codes for unit 13.......................................................................................................12
- How to create a contingency table...................................................................... 12
- How to create a scatterplot.............................................................................. 12
R specific codes for unit 24.......................................................................................................12
- To compute the association between two variables............................................ 12
- Compute Spearman’s rho................................................................................... 13
- Cramer’s V.......................................................................................................... 13
- Compute Kendall’s tau........................................................................................ 13
, R specific codes for unit 16.......................................................................................................13
- How to compute variables from characters to ordered factors/ordinial variables....
13
- Create a bivariate 2x2 table (with the correct percentages)................................13
- Create a contingency table to analyse the trivariate hypothesis using the three
dichotomous variables...........................................................................................14
R specific codes for unit 17.......................................................................................................14
R specific codes for unit 18.......................................................................................................14
- Create a stacked bar chart..................................................................................14
- How to make a stacked bar chart look ‘nicer’..................................................... 14
- Create a stacked bar chart using percentages.............................................. 14
- How to make a multiple stacked bar chart for a trivariate relationship................15
Unit 13 - Visualizing and analyzing bivariate relationships in R......................................... 15
How to use contingency tables (always two nominal/ordinal)................................................................ 15
Scatterplot (quantitative variables)......................................................................................................... 16
Unit 24 - Describing the association between two variables............................................17
Example of the Pearson’s R:.............................................................................. 19
More examples of relationships in graph (positive/negative linear or
curvilinear relationship):.................................................................................... 19
To compute Pearson R we use this formula.....................................................20
Unit 12 - Causality and bivariate causal hypotheses........................................................ 20
Time order problems:.................................................................................................. 22
Association:.................................................................................................................23
The effect of third variables in a bivariate relationship:............................................... 24
Confounding:......................................................................................................... 24
Interaction:.............................................................................................................24
Unit 14 - Causality and the effect of third variables.......................................................... 25
How to formulate a trivariate hypothesis:.................................................................... 25
Examples with all the elaboration models:............................................................ 25
Confounding/explanation............................................................................................ 26
Confounding in a graph:........................................................................................ 27
Interpretation............................................................................................................... 27
Interpretation in a graph:....................................................................................... 28
Interaction/modification............................................................................................... 28
Interaction/modification in a graph:....................................................................... 29
Addition....................................................................................................................... 29
Addition in a graph:............................................................................................... 30
More examples:...........................................................................................................30
Unit 15 - Research designs for testing causal hypotheses.............................................. 31
Cross-sectional design:......................................................................................... 31
Definition......................................................................................................... 32
Interrupted time series...........................................................................................32
Definition......................................................................................................... 32
Classical experiments........................................................................................... 32
Definition:........................................................................................................ 33
, Four types of validity in the context of causal inference:.......................................34
Statistical conclusion validity:................................................................................ 35
Internal validity:..................................................................................................... 35
Measurement & sampling validity:.........................................................................35
External validity:.................................................................................................... 35
Notation of research designs.................................................................................35
Unit 16 - Elaboration: analyzing multi-variate relationships using tables.......................36
Association: find out the expected direction and substance and significance.............37
Direction................................................................................................................ 37
Substance............................................................................................................. 37
Significance........................................................................................................... 38
Type 1 and type 2 error................................................................................... 38
Unit 17 - Elaboration: analyzing multi-variate relationships using tables.......................38
Unit 18 - Visualizing multivariate relationships using R................................................... 39
Unit 19 - Sampling.................................................................................................................40
Non-probality sampling............................................................................................... 41
Convenience sample.............................................................................................41
Purposive sample..................................................................................................41
Snowball sampling................................................................................................ 42
Quota sampling..................................................................................................... 42
Probablity sampling.....................................................................................................42
Simple random sampling.......................................................................................42
Systematic random sampling................................................................................ 42
Stratified random sampling....................................................................................43
(multi-stage) cluster sampling............................................................................... 43
Sampling bias (bias, sample size not important).........................................................44
Sampling error (no bias, sample size important).........................................................45
Unit 23 - Normal distribution................................................................................................45
Cumulative distribution function (CDF)..................................................................45
The empirical rule (68 – 95 – 99).......................................................................... 45
Unit 20 - First steps towards inference: certainty about means...................................... 47
Sampling distribution of the sample mean.................................................................. 47
Central limit theorem................................................................................................... 48
Important differencenes in notation....................................................................... 48
The formula of the standard deviation of the sampling distribution....................... 49
Population SD not known...................................................................................... 49
Kurtosis................................................................................................................. 50
95% confidence interval (CI) of the mean............................................................. 50
The difference between inferential statistics and descriptive statistics....................... 51
Unit 22 - Research ethics..................................................................................................... 51
Summary of the IRM short guide.........................................................................................3
1. Research Questions and Research Types................................................................................ 4
2. Conceptualization and Hypothesis Formulation......................................................................4
3. Operationalization and Data Collection.................................................................................. 4
4. Data Analysis with Cross-Tabulations (Crosstabs)................................................................... 5
5. The Elaboration Model...........................................................................................................5
6. Trivariate Analysis: Why It Matters.........................................................................................7
R specific codes................................................................................................................... 7
R specific codes for unit 4...........................................................................................................7
o Load a package....................................................................................................7
- View the dataset.................................................................................................. 7
- If you are interested in just one variable of the dataset,........................................7
- explore a variable in your dataset......................................................................... 7
- Load a CSV file..................................................................................................... 7
current working directory......................................................................................... 7
- If you want to find the variables in the data file,.................................................... 7
- Create a new dataset with only two variables from the dataset............................ 8
- How to filter in a dataset:.......................................................................................8
- How to clean the global environment.................................................................... 8
R specific codes for unit 7................................................................................................... 8
R specific codes for unit 9...........................................................................................................8
- How to make a frequency table.............................................................................8
- How to make a histogram..................................................................................... 8
- Change bin width.................................................................................................. 8
- Recoding a variable (mutate)................................................................................ 9
- How to make frequency tables..............................................................................9
- How to make bar charts........................................................................................ 9
R specific codes for unit 11.......................................................................................................10
- Compute the mean..............................................................................................10
- Compute the standard deviation......................................................................... 10
- Computer the variance........................................................................................10
- How to make a boxplot........................................................................................10
- How to use multiple variables into one boxplot................................................... 10
Standardizing Variables......................................................................................10
R specific codes for unit 13.......................................................................................................12
- How to create a contingency table...................................................................... 12
- How to create a scatterplot.............................................................................. 12
R specific codes for unit 24.......................................................................................................12
- To compute the association between two variables............................................ 12
- Compute Spearman’s rho................................................................................... 13
- Cramer’s V.......................................................................................................... 13
- Compute Kendall’s tau........................................................................................ 13
, R specific codes for unit 16.......................................................................................................13
- How to compute variables from characters to ordered factors/ordinial variables....
13
- Create a bivariate 2x2 table (with the correct percentages)................................13
- Create a contingency table to analyse the trivariate hypothesis using the three
dichotomous variables...........................................................................................14
R specific codes for unit 17.......................................................................................................14
R specific codes for unit 18.......................................................................................................14
- Create a stacked bar chart..................................................................................14
- How to make a stacked bar chart look ‘nicer’..................................................... 14
- Create a stacked bar chart using percentages.............................................. 14
- How to make a multiple stacked bar chart for a trivariate relationship................15
Unit 13 - Visualizing and analyzing bivariate relationships in R......................................... 15
How to use contingency tables (always two nominal/ordinal)................................................................ 15
Scatterplot (quantitative variables)......................................................................................................... 16
Unit 24 - Describing the association between two variables............................................17
Example of the Pearson’s R:.............................................................................. 19
More examples of relationships in graph (positive/negative linear or
curvilinear relationship):.................................................................................... 19
To compute Pearson R we use this formula.....................................................20
Unit 12 - Causality and bivariate causal hypotheses........................................................ 20
Time order problems:.................................................................................................. 22
Association:.................................................................................................................23
The effect of third variables in a bivariate relationship:............................................... 24
Confounding:......................................................................................................... 24
Interaction:.............................................................................................................24
Unit 14 - Causality and the effect of third variables.......................................................... 25
How to formulate a trivariate hypothesis:.................................................................... 25
Examples with all the elaboration models:............................................................ 25
Confounding/explanation............................................................................................ 26
Confounding in a graph:........................................................................................ 27
Interpretation............................................................................................................... 27
Interpretation in a graph:....................................................................................... 28
Interaction/modification............................................................................................... 28
Interaction/modification in a graph:....................................................................... 29
Addition....................................................................................................................... 29
Addition in a graph:............................................................................................... 30
More examples:...........................................................................................................30
Unit 15 - Research designs for testing causal hypotheses.............................................. 31
Cross-sectional design:......................................................................................... 31
Definition......................................................................................................... 32
Interrupted time series...........................................................................................32
Definition......................................................................................................... 32
Classical experiments........................................................................................... 32
Definition:........................................................................................................ 33
, Four types of validity in the context of causal inference:.......................................34
Statistical conclusion validity:................................................................................ 35
Internal validity:..................................................................................................... 35
Measurement & sampling validity:.........................................................................35
External validity:.................................................................................................... 35
Notation of research designs.................................................................................35
Unit 16 - Elaboration: analyzing multi-variate relationships using tables.......................36
Association: find out the expected direction and substance and significance.............37
Direction................................................................................................................ 37
Substance............................................................................................................. 37
Significance........................................................................................................... 38
Type 1 and type 2 error................................................................................... 38
Unit 17 - Elaboration: analyzing multi-variate relationships using tables.......................38
Unit 18 - Visualizing multivariate relationships using R................................................... 39
Unit 19 - Sampling.................................................................................................................40
Non-probality sampling............................................................................................... 41
Convenience sample.............................................................................................41
Purposive sample..................................................................................................41
Snowball sampling................................................................................................ 42
Quota sampling..................................................................................................... 42
Probablity sampling.....................................................................................................42
Simple random sampling.......................................................................................42
Systematic random sampling................................................................................ 42
Stratified random sampling....................................................................................43
(multi-stage) cluster sampling............................................................................... 43
Sampling bias (bias, sample size not important).........................................................44
Sampling error (no bias, sample size important).........................................................45
Unit 23 - Normal distribution................................................................................................45
Cumulative distribution function (CDF)..................................................................45
The empirical rule (68 – 95 – 99).......................................................................... 45
Unit 20 - First steps towards inference: certainty about means...................................... 47
Sampling distribution of the sample mean.................................................................. 47
Central limit theorem................................................................................................... 48
Important differencenes in notation....................................................................... 48
The formula of the standard deviation of the sampling distribution....................... 49
Population SD not known...................................................................................... 49
Kurtosis................................................................................................................. 50
95% confidence interval (CI) of the mean............................................................. 50
The difference between inferential statistics and descriptive statistics....................... 51
Unit 22 - Research ethics..................................................................................................... 51
