What does the mean?

Mean is a measure of central tendency, which is a way of summarizing the average value of a set of numbers. It is calculated by adding up all the numbers in the set and then dividing by the number of numbers in the set.

For example, if you have the set of numbers {1, 2, 3, 4, 5}, the mean is calculated as follows:

```

(1 + 2 + 3 + 4 + 5) / 5 = 3

```

Therefore, the mean of the set {1, 2, 3, 4, 5} is 3.

The mean is a useful measure of central tendency because it is relatively easy to calculate and it gives a good indication of the average value of a set of numbers. However, it can be misleading if there are outliers in the set, which are values that are much higher or lower than the rest of the numbers in the set. In such cases, the median or the mode may be more appropriate measures of central tendency.