Using standard deviation, we can estimate where the elements of a dataset are located. Suppose we have n elements, \overline{x} is the arithmetic mean, and SD is the standard deviation. By the Laguerre-Samuelson inequality we know that elements from this dataset are located in the interval:
Let's see what this means for the particular set sizes where the arithmetic mean is zero (\overline{x}=0) and standard deviation equals one (SD = 1) or two (SD = 2).