› Forums › Spectroscopy › Help with ISIS › RMS calc
13 January 2017 at 11:38 am
#577809
![](https://britastro.org/wp-content/uploads/2018/02/picture-404-1519126148-80x80.jpg)
Participant
Hi David/Robin,
I am wondering if my interpretation of RMS performance index reported for dlambda is incorrect in this instance? It appears to be sqrt of sum of squares/3. [3 being order of polynomial -1].
john