Читать книгу Medical Statistics - David Machin - Страница 50

The median and quartiles are example of percentiles – points which divide the distribution of the data set into percentages above or below a certain value. A percentile (or a centile) is a measure used in statistics indicating the value below which a given percentage of observations in a group of observations fall. For example, the 20th percentile is the value (or score) below which 20% of the observations may be found. The median is the 50th percentile, the lower quartile is the 25th percentile and the upper quartile is the 75th percentile. With enough data any percentile can be calculated from continuous data.