# IB Mathematics (HL)/Statistics

A statistic is a single number that represents or helps to describe one aspect of a data set.

By calculating a statistic, you summarise the data and lose detail. Usually, this means you cannot recreate the original data, even from a collection of statistics.

Examples of statistics include: the mode, median, mean and range (of discrete data), estimated mean, estimated median and modal class of grouped data, interquartile range.

For IB you also need to know the meaning and method for finding the mean and standard deviation of data sets. The mean is an example of a statistic that measures location. The standard deviation is a an example of a statistic that measures dispersal, or spread. It is common when comparing data sets to comment about both dispersal and location.