Hi XOR. Indeed, formulas in mentioned cells (AI:AO, R9-11-13) gives STDEV values much different from the 'real' stdev as mentioned in cells N:S, R 9-13. The real ones are based on a simple stdev formula from a particlar range while the former ones are based on a formula using criteri (B, H, 1, 6). I gues there must be something wrong with either formula or formatting of particular empty cells?
(The dataset in the Excel file is just a small piece of a big dataset, thats what I meant with huge)
R