Before you edited a perfectly good reply to CB to what I have, unfortunately, had to quote (and which, to be honest, is useless compared to what you had originally posted in reply to CB), what you said contained important information. Next time post the whole problem.
From what you said before deleting it, the sd deviation you're talking about cannot be calculated without knowing the values of X. Then apply the usual formula to the data. Formulas can be found using Google.
Thread closed.