- The arithmetic mean of a set of numbers is the sum of numbers divided by the number of numbers in the set : Mean = sum of the numbers/number of numbers
- It is most the reliable measure provided there are no extreme values in the data because all the values in the data are used in calculating.
- Whenever the set of data contains extreme values, the median or mode would probably be more reliable because they are not influenced by extreme values.
- The number which occurs most frequently in a set of numbers
- It is most useful in business planning as a measure of popularity that reflects central tendency or opinion.
- May be preferred as a measure of central tendency for describing economic, sociological and educational data.
- The median is popular in the study of social sciences because much of the data in the social sciences contain extreme values, in the set of household incomes.
- Median for an odd number of numbers is the middle number when the numbers are arranged in order of magnitude (i.e. ascending/descending order)
- Median for an even number of numbers is the mean of the two middle numbers when the numbers are arranged in order of magnitude