In math, the mean is the average of a set of numbers. To find the mean of a data set, add up all of the numbers in the set, and then divide that total by the number of numbers in the set.
A Measure of Central Tendency
In statistics, the mean is one of the three measures of central tendency, which are single numbers that try to pinpoint the central location within a data set. The mean, or average, is used most commonly, but it is important to differentiate it from the two other measures: median and mode. The median is the middle number when the numbers are listed in ascending order, while the mode is the most frequently occurring number.
Suppose you are asked to find the mean of the daily high temperatures for the last four days, which were recorded as 72, 72, 84 and 68 degrees Fahrenheit. Add 72 + 72 + 84 + 68, which equals 296. Divide 296 by 4, producing a result of 74. Thus, the mean of the data set describing the temperatures over the past four days is 74 degrees Fahrenheit.