CH 10 · notes
How it works
Paste replicate assay values. The page counts n, computes the mean, then the standard deviation (sample n−1 by default, or population n when selected). Percent relative standard deviation is %RSD = (SD ÷ |mean|) × 100. An optional acceptance limit marks PASS when %RSD is at or below the limit.
Worked example
Values 10.02, 10.05, 9.98, and 10.01 with sample SD give mean 10.02, SD 0.02887, and %RSD 0.2882%. Load example fills the same numbers.
Related tools
For single-step dilutions see the C1V1 calculator. Solution preparation is on the Molarity calculator.
FAQ
What is %RSD?
%RSD is the relative standard deviation as a percent: SD divided by the absolute value of the mean, times 100. It summarizes scatter among replicate values on the same scale as the mean.
When should I use sample SD versus population SD?
Sample SD (n−1) is the default for a set of replicates that stand for a larger process. Population SD (n) treats the entered values as the whole set. Assay QC usually uses sample SD.
Why is %RSD blank when the mean is zero?
Division by a zero mean is undefined. The page still shows n, mean, and SD, and lights MEAN ZERO. Shift or rescale the data before using %RSD.
Does the page upload my numbers?
No. The calculation stays in the browser. The panel notice is the data statement for this page.