as stated in post heading. *equation meant to be formula lol
Im confused, could somebody give me the forumla for standard deviation? x
No the sample SD:
$\displaystyle
s = \sqrt{\frac{1}{n}\sum_1^n (x_i - \bar{x})^2}
$
Or for the estimator of the population SD
$\displaystyle
s = \sqrt{\frac{1}{n-1}\sum_1^n (x_i - \bar{x})^2}
$
or sample SD for grouped data:
$\displaystyle
s = \sqrt{ \frac{\sum_1^n n_i (x_i - \bar{x})^2}{\sum_1^n n_i}}
$
where there are $\displaystyle n$ groups with group marks $\displaystyle x_i$ and frequency count $\displaystyle n_i$.
ZB