Hi all - quick question about this exam question. "Monthly standard deviation of the log share price": what is that actually? At least, judging from the examiners' solutions, it seems to be sqrt ( E( [log S(t+1) - log S(t)]^2 |S(t)) ). But why? That doesn't seem to be a standard deviation, E( log S(t+1)) isn't log S(t). I'd be grateful if anyone can shed any light. Louisa
