Definition
Representative sample
A sample that reflects the target population in the characteristics that matter for the question.
What it means
A sample does not need to match the population in every possible way. It needs to include the relevant groups and patterns well enough for the question. A large sample taken from only one convenient corner can still give a misleading picture.
Remember it
A useful mini-version of the population for the feature being studied.
Example
A two-campus school wants to estimate travel time for all learners. The sample includes learners from both campuses and every year group, instead of asking only children waiting at one gate.
Watch for
A large online poll of volunteers may still be unrepresentative if people without internet access or people who choose not to reply differ in ways that matter.
Common mix-up
Random sampling tends to produce representative samples, but one random sample can still be uneven by chance.
Exact meaning
A representative sample resembles the target population in the characteristics relevant to the investigation closely enough to support suitable conclusions about that population.