Week 1 · Introduction. Descriptive statistics
Population and sample. Description and inference. Univariate data, central tendency and the box plot
Two decks open the programme. Part 1 sets up the vocabulary the whole course uses: population and sample, sampling designs and their limits, and the difference between describing a sample and inferring something about a population. Part 2 turns to describing one variable at a time: the median, the mean, outliers, weighted averages and the box plot, with worked examples on nutrient intake, global poverty and the world income distribution.
Part 1. Introduction
Subtitle: Population and Sample. Description and Inference.
| Material | WS 2024/25 | WS 2023/24 |
|---|---|---|
| 🖥 Interactive slides | Week 01. Part 1. Introduction | not rendered (sources were revised for 2024/25) |
| 📄 PDF from Ilias | Week 01. Part 1. Introduction.pdf · 38 pages · added 14 Oct 2024 | Week 01. Part 1. Introduction.pdf · 42 pages · added 6 Dec 2023 |
| 💻 Source | mk68-01-p1-slides.qmd |
mk68-01-p1-slides.qmd |
What the deck covers
- The population: what it is and why we rarely observe all of it.
- Sampling: the simple random sample, the law of large numbers in action and its limitation, what a simple random sample cannot do, and the stratified, cluster and multistage designs that address it.
- Population and samples by research question.
- How to conclude about a population from a random sample: descriptive versus inferential statistics, the process of statistical inference, and the basics of a statistical hypothesis.
- Goals of the quantitative part of the course.
- Homework: an example of statistical inference in a research project (question, design, two waves of data collection, analysis).
- Takeaways checklist, key concepts and example exam questions.
Part 2. Descriptive statistics
Subtitle: Univariate Data. Central tendency. Box plot.
| Material | WS 2024/25 | WS 2023/24 |
|---|---|---|
| 🖥 Interactive slides | PDF only, see the note below | not rendered |
| 📄 PDF from Ilias | Week 01. Part 2. Descriptive statistics.pdf · 53 pages · added 14 Oct 2024 | Week 01. Part 2. Descriptive statistics.pdf · 54 pages · added 6 Dec 2023 |
| 💻 Source | mk68-01-p2-slides.qmd |
mk68-01-p2-slides.qmd |
What the deck covers
- Univariate data.
- Central tendency: individuals’ nutrient consumption in the DR Congo as the running example; describing a distribution; the median; the arithmetic mean; extreme and influential observations and how to deal with them; the weighted mean, illustrated with the average extreme poverty rate in the world; exam problems on central tendency.
- The box plot: describing a single variable and comparing distributions.
- The global income distribution: the logarithm transformation and the insights it reveals about data complexity and change over time.
- Comparing distributions of income between regions with box plots.
The deck reads materials/data/poverty-population.csv, a country-level extract of extreme poverty rates and population used for the weighted-mean example. CSV files are excluded from the public repository, so the deck is not in the render list. The PDFs above are the versions the students received. See the README for how to render it locally once the file is in place.
Data used
- 📊 DR Congo nutrition (
congo-nutrition.rds) and the world income distribution (income-distribution.rds), both in Part 2. - The sampling examples in Part 1 use simulated populations.
Where the course goes next
← Week 0 · Prerequisites · → Week 2 · Distribution, variance and its applications