How to calculate Standard Deviation in ONE Desktop?Tutorial
The standard deviation measures the spread of the data about the mean value. It is useful in comparing sets of data which may have the same mean but a different range. For example, the mean of the following two is the same: 18 19 20 21 22 = 18+19+20+21+22 / 5 = 20 10 15 20 25 30 = 10+15+20+25+30 / 5 = 20 However, the second is clearly more spread out. If a set has a low standard deviation, the values are not spread out too much. Lets do the calculations outside of ONE Desktop, so we know our expected result. Example Find the standard deviation of 4, 9, 11, 12, 17, 5, 8, 12, 14?First work out the mean: 4+9+11+12+17+5+8+12+14 / 9 = 10.222Now, subtract the mean individually from each of the numbers given and square the result. This is equivalent to the (x - )² step. x refers to the values given in the question. x 4 9 11 12 17 5 8 12 14 (x - )2 38.7 1.49 0.60 3.16 45.9 27.3 4.94 3.16 14.3 Now add up these results (this is the 'sigma' in the formula): 38.7+1.49+0.60+3.16+45.9+27.3+4.94+3.16