# Data Analysis and Inference

Learning from STAT206.

The bad:

- Inductive, rather than deductive
- Errors
- Formulas appear from nowhere

The good:

- Useful

### Concepts

Collecting Data The goal: Ensure your data is representative of the population.

Biased data: Systematic errors in data collection.

- Numeris
- Psychology

Example solution: Having a TA per question, so the aggregate grades are what a student deserves.

Measure of Central Tendency

Measures of Dispersion and Symmetry

- Rang = max - min
- $IQR=Q_{3}−Q_{1}$, where IQR is the inter-quartile range
- Variance (or Variance (or Standard Deviation)
- Skewness - measures bias towards left or right side
- Kurtosis - Measure of normality

### Plotting

- Violin Plot
- Boxplot