stdDev = sqrt ( sum( CONCsample - CONCavg)**2) / (N-1)

where N is the number of samples and CONC is the concentration

The result multiplier will depend on the number of samples
used for the calculation and the level of confidence required.

**Instrument Detection Limit**

Instrument Detection Limits is based on two
samples - a Blank and a Standard, and the concentration list
associated with the standard.

The IDL is calculated as follows:

IDL = (Multiplier * StdDev Blank) /
Slope

**Background Equivalent Concentration**