Is there any one who could help me out in suggesting the corrected statistical tool to be used for evaluating intermediate precision of a method to be done

furher to this I am also interested to know how to calculate cumilative RSD

We determine intermediate precison using 6 data sets consisting of 6 replicate analyses performed by 2 different analysts for a total of 36 data points, 18 by each analyst. Each set of 6 replicate analyses (a trial) is performed on a different day from start to finish using new standard and sample preparations. The variance for each replicate (1 through 6) is calculated using the data for that replicate in each trial, providing a measure of the day to day variability in the analysis. Then, the pooled within laboratory variance is calculated by averaging the individual variances determined for each of the 6 replicate analyses. Finally, the RSD is calculated by dividing the square root of the pooled variance by the average assay from all analyses, then multipying by 100. Somewhat difficult to explain, however, once you do it, the logic becomes more clear. We have the formulas set up in a spreadsheet format whch makes makes it very easy. Using the same data set, we also calculate the within analysis variation and repeatability in a similar fashion.

I'm unfamiliar with cumilative RSD.

Best Regards,

Michael Hinsberg
http://www.hinsbarlabs.com