1. Introduction to Statistics

• Definition and scope of statistics
• Two meanings:
  • Statistics as data → e.g. employment statistics, accident statistics.
  • Statistics as methods → collection, organization, analysis, interpretation.

2. Populations, Samples, and Types of Statistics

• Population: Entire group under study (finite or infinite).
• Sample: Subset of the population.
• Inductive (Inferential) Statistics: Drawing conclusions about populations from samples; involves probability.
• Descriptive Statistics: Summarising data without generalising beyond it.

3. Variables and Data Types

• Variables: Symbols (X, Y, etc.) representing measurable characteristics.
• Constants: Fixed values.
• Types of Variables:
  • Discrete → countable values (e.g. number of children).
  • Continuous → measurable values within a range (e.g. height, weight).
• Data Types: Discrete data vs continuous data.
• Extension to categorical variables (e.g. colours, labelled numerically).

4. Rounding of Data

• Rules for rounding numbers:
  • Round to nearest unit/decimal.
  • Special case: numbers ending with 5 → round to nearest even integer (minimises cumulative error).