Frequency distribution
A frequency distribution groups observations into categories or class intervals and records how many fall in each, showing where data concentrates. It is the basis for histograms and the starting point for any data summary.
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Fifty customers' monthly spending is grouped into four class intervals: 12 spend €0–100, 20 spend €100–200, 11 spend €200–300, and 7 spend €300 or more. The bulge in the €100–200 band shows at a glance where typical customers sit, a pattern a raw list of fifty numbers could not reveal nearly as quickly.
Where it fits
TopicFoundations: Data, Populations & SamplingCoreTopicDescriptive StatisticsCoreSubjectData Analysis & StatisticsCore
Check yourself
PracticeCORE
An analyst records weekly purchase-order volumes for 40 weeks and groups the data into eight equal-width class intervals. For one interval she computes a relative frequency of 0.20. What does this figure represent?
Select an answer to check your understanding.