Standard deviation

The standard deviation is calculated with the formula for the population standard deviation:

σ	Standard deviation
N	Number of samples
x_i	Measured value response or amount. For the curve model Average RF, it is the response factor RF of a compound in a single sample.
μ	Mean value. For the curve model Average RF, it is the average response factor of a compound in all samples.

NOTE

For the curve model Average RF: Due to the normally rather small population (number of calibration points), this formula is used instead of the sample population standard deviation (with N-1 as denominator).