Module 9: Background You’ll Need 2

  • Distinguish between a statistic and a parameter.
A population is an entire group of people, animals, items, etc. that we are interested in drawing conclusions about. (Often from a research study). We rely on population samples to make inferences because it is often challenging or impossible to collect data on every item in a population.

  • A parameter is a number that describes a population.
  • [latex]p[/latex] represents the parameter, a population proportion.

A sample is a specific subgroup of a population. We use samples to make inferences or judgments about a population.

  • A statistic is a number that we calculate from a sample.
  • [latex]\hat{p}[/latex] is the notation for a sample proportion, a statistic.