Numerical Data Types Overview

Jul 11, 2025

Overview

This lecture explains the difference between discrete and continuous numerical data, provides examples, and offers strategies for identifying each type.

Types of Numerical Data

  • Numerical data is divided into discrete and continuous categories.
  • Discrete numerical variables have outcomes that are only counting numbers (e.g., 0, 1, 2, 3).
  • Continuous numerical variables can take any value in a range, including decimals and fractions.

Discrete Numerical Data

  • Only whole numbers make sense for discrete data (e.g., number of dogs owned: 0, 1, 2).
  • Examples: number of books read, dice roll outcomes, number of iPhones in a classroom, number of kittens in a litter.
  • "Does one half make sense?" is a guiding question; if not, the variable is discrete.

Continuous Numerical Data

  • Continuous variables can be measured to any level of precision within a range (e.g., 10.5, 25.8).
  • Examples: distance, time, weight, volume, concentration of sodium, height, money (as typically used).
  • If half or decimal values make sense (like half a pound), the variable is continuous.

Application Examples

  • Weight of a newborn kitten: continuous.
  • Number of kittens in a litter: discrete.
  • Height of people in a course: continuous.
  • Number of iPhones in class: discrete.
  • Concentration of sodium in blood: continuous.
  • Inches of rainfall in a day: continuous (measurement, not count of items).
  • Total of last grocery bill: continuous, unless counting exact pennies.

Key Terms & Definitions

  • Discrete Numerical Variable — a variable with only whole number outcomes (counting numbers).
  • Continuous Numerical Variable — a variable with outcomes over any value in a range, including fractions and decimals.

Action Items / Next Steps

  • Complete example two: label each scenario as "D" for discrete or "C" for continuous based on the provided criteria.