QUAN 102 - Module 1 & 2

Models & populations, variables, samples, bar graphs & histograms

Model

An abstraction of a system, aimed at understanding, communicating, explaining, or designing aspects of interest of that system

Population

All the values, people or objects we are interested in knowing something about

Variable

A characteristic of members of the population

If the population is ‘NZ dairies’, what could variables include?

Location, income

What values does a quantitative variable have?

Numbers

Quantitative discrete variable

Whole number values only

Quantitative continuous variable

Measurements and decimal numbers

Ordinal categorical variable

categories have a logical order

What sort of variable is ‘mild, medium, hot’?

Ordinal categorical

Nominal categorical

Named categories

Sample

Gather data from a subset of the wider population

What sampling method is used to achieve a good representation of the population?

Random sampling

Mode

The category which has the most observations

Is the mean a good summary of central tendency for quantitative variables?

Yes

Dummy variable

A variable assigned 0 or 1 depending on whether it meets criteria