1. First calculate VWAP, then take a avg of last 10 days, given it a name x,
2.Next column-deduct VWAP of 10th day MInus x in the same row, give it a name .A10,
3. Next column take A10^2, say B10,
4. divide B10 / 10, Say C10,
5.Take Sq Rt of it, say D10 = SD,
6. x+- 1*D10 , would be your SD of +- 1 band, and so on
7. x+- 2*D10 , would be your SD +-2 Band
Regards,
Paras