I'm reading 'The Scientist and Engineer's Guide to Digital Signal Processing'. It says for a noisy signal, the important parameter is not the deviation from the mean, but the power represented by the deviation from the mean.
So, if I were to consider Amplitude it would just be voltage deviations from the mean, but for power it becomes Voltage^2 deviations. Then an average is taken and a square root to give the standard deviation [It would just be an average deviation in the case of the Amplitude].
I'm trying to understand why considering just the Amplitude is not good enough? Why is it that when I'm dealing with noisy signals, I need to consider power calculations to try and reduce the noise?