Читать книгу Medical Statistics - David Machin - Страница 39

A quantitative measurement contains more information than a categorical one, and so summarising these data is more complex. One chooses summary statistics to condense a large amount of information into a few intelligible numbers, the sort that could be communicated verbally. The two most important pieces of information about a quantitative measurement are ‘what is the average value?’ and ‘what is the spread of the data?’ These are categorised as measures of location (sometimes ‘central tendency’) and measures of spread or variability. A measure of location (average) and variability (spread) provides an informative but brief summary of a set of observations.