Hi, everyone
I am wondering how to calculate the intermediate precision during the validation of a new analytical method (for soil analysis). Please see the example below:
For one soil sample (10 replicas), the new method on one day give results as 2.5, 2.7, 2.4, 2.6, 2.8, 2.4, 2.7, 2.4, 2.3, 2.9 mg/kg soil. On the other day, this new method (with another analyst, the same laboratory) give results as 2.4, 2.6, 2.6, 2.8, 2.9, 2.3, 2.5, 2.9, 2.3, 2.5. Please help with the intermediate presicion ?
Thanks a lot
Tho Nguyen
Maybe you have a look at
https://sisu.ut.ee/lcms_method_validation/41-precision-trueness-accuracy
Tobias
Hi, intermediate precision can be calculated by ANOVA. Intermediate precision/ variance = overall variance = (inter serial- variance + intra -serial variance); intra-serial variance = MS within (ANOVA); inter-serial variance = variance run (can be calculated by equation that described by USP 41
The article "Intermediate precision determination at validation of methods in pharmacy" (rus) discusses 6 ways to define Intermediate precision. Methods 1, 3 and 4 are generally accepted. You can use any of them: https://www.researchgate.net/publication/309858467_INTERMEDIATE_PRECISION_DETERMINATION_AT_VALIDATION_OF_METHODS_IN_PHARMACY
A free translator of large texts is available for translation from Russian to English https://www.m-translate.ru/translator/text
Calculate individual standard deviation for day one and other day determinations also calculate cumulative standard deviation for all the determination. Confirm wheter it fit in your predefined acceptance criteria. Find below link for calculation or alternately you can use excel sheet. calculate relative standard deviation by formula RSD= Std.deviation/Mean
https://www.hackmath.net/en/calculator/standard-deviation
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