For the less mathematically incline the standard deviation is a way of measuring the average difference from the mean, with big differences counting slightly more.
Around 70% of teams will finish within 1SD of their finishing position , 95% of teams should finish within 2sd.
So lets say your predicted position was 10th, and the SD was 3
There would be a 70% chance of you finishing between 7 and 13 and a 95% chance you will finish between 4th – 16th, i.e. there is very little chance you should gain automatic relegation or promotion.
So looking at each division
Division 1: +/- 3.0
Division 2: +/- 6.6
Division 3: +/- 7.8
Division 4: +/- 7.0
Division 5: +/- 5.8
So what does this mean. Division 1 and Division 5 are the less varied in terms of performance. For example if you are ranked 20th the chance is you will finish no higher than 17th and definitely no higher than 14th no matter what you do.
Why is this, well over 5 seasons the cream has risen to the top and the other stuff has stayed or sunk to it’s true level.
Division 3 remains the melting pot for the top 100, better teams going up, worse teams going down, but hope for all.
The 8th placed team could well finish top in D3 ,the 20th placed team could finish 4th..
There is a strong arguement to use the standard deviation to work out true value added across all 5 divisions. This perhaps put the relative performances of Napoli and Juventus in D1 into true perspective.