Determine the standard variation of the data below. (1, 2, 3, 4, 5)

Calculate for the mean/ average of the given numbers:
 
                             μ = (1 + 2 + 3 + 4 + 5) / 5 = 3

Then, we calculate for the summation of the squares of differences of these numbers from the mean, S
 
                             S  = (1 - 3)² + (2 - 3)² + (3 - 3)² + (4 - 3)² + (5 - 3)²
                                S = 10

Divide this summation by the number of items and take the square root of the result to get the standard deviation.

                              SD = sqrt (10 / 5) = sqrt 2  
                                    SD = 1.41

Thus, the standard deviation of the given is equal to 1.41.