Signal to Noise calculation

[m-j-keller]

One of the parameters MS-DIAL reports in the alignment export is the "S/N average". Is this referring to the signal to noise ratio of the chromatographic peaks or the S/N of the actual mass spectrometric peak? Can anyone tell me the formula for how S/N is calculated? I checked the tutorial, but I didn't see anything there. I'm still using MS-DIAL 4 in case it's different in 5.

Thanks!