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Delete - Last Modified By: BJO at 15/02/2015 11:05:34 AM
Data are not just data! We can link data to its type. For example, think of the data that is about you. Your sex, height, body-type, weight etc. are all data that have specific types.
Sex – can be one of two things, ‘female’ and ‘male’. This is what we call categorical data, putting something into a category where nothing is ‘ordered’ i.e ‘male’ is not ‘bigger’ than ‘female’ (or vice versa!).
Height – is usually specified as a number, maybe in centimetres or metres. This is what we call numerical data. If we specified that height data had to be measured to the nearest whole centimetr (e.g. 173 cm), then we can call this discrete numerical data – only whole numbers are allowed. If we allow the height measurement to take any value (e.g. 1.732 metres), then we call this continuous numerical data.
You need to understand the different types of data: categorical and numerical. If the data are numerical, then you also need to understand the difference between discrete and continuous numerical data.
Examples:
- Sex: Categorical – e.g. female or male.
- Body-type: Categorical – e.g. endomorphic, mesomorphic, ectomorphic.
- Height: Numerical, and usually continuous and discrete e.g. most people quote their height to the nearest whole centimetre, but express it in continuous metres. Your author is “one seventy three” (metres).
Weight: Numerical and usually discrete. Most people quote their weight to the nearest whole kilogram.