Hi using stdev(roc(c,13,%),100) I can plot the stdev for roc over 100 periods. Is it possible though to plot the stdev of price data from day 1. Eg say first 100 periods stdev = x, then 101 = x1, 102 = x2 etc. Basically adding a period recalculating stdev and plotting, but retaining the day befores on the chart. Also how can I do the same but this time calculate the average of the roc. Regards Robert