# Mean median mode sd

**Keywords:** mean, median, mode, average, middle, range, difference, occurs, most, often, algebra, lesson, homework, purplemath

**Description:** Explains how to compute the mean, median, mode, and range of a list of numbers.

Mean, median, and mode are three kinds of "averages". There are many "averages" in statistics, but these are, I think, the three most common, and are certainly the three you are most likely to encounter in your pre-statistics courses, if the topic comes up at all.

The "mean" is the "average" you're used to, where you add up all the numbers and then divide by the number of numbers. The "median" is the "middle" value in the list of numbers. To find the median, your numbers have to be listed in numerical order, so you may have to rewrite your list first. The "mode" is the value that occurs most often. If no number is repeated, then there is no mode for the list.

Note that the mean isn't a value from the original list. This is a common result. You should not assume that your mean will be one of your original numbers.

There are nine numbers in the list, so the middle one will be the (9 + 1) ÷ 2 = 10 ÷ 2 = 5 th number: