Hmm, I think you’re on the right track with z-scores for normalizing data to a 3 sigma model. But have you considered using min-max scaling as an alternative? It’s not exactly the same, but it can help if you’re dealing with data that’s not normally distributed.
Also, if you’re using Excel, you can calculate z-scores manually using the formula =(A1-AVERAGE(A:A))/STDEV.P(A:A). Just drag it down, and you’re good to go. But yeah, watch out for those pesky outliers!
Also, if you’re using Excel, you can calculate z-scores manually using the formula =(A1-AVERAGE(A:A))/STDEV.P(A:A). Just drag it down, and you’re good to go. But yeah, watch out for those pesky outliers!