ryMath101

$$f(x; \mu, \sigma) = \frac{1}{\sigma \sqrt{2 \pi}} e^{ -      \frac{(x-\mu)^2}{2\sigma^2} }$$


$$\Psi(e;\mu,\sigma) = \int_{\mu-e}^{\mu+e}{f(x; \mu, \sigma)dx}$$

e	$1\sigma$	$2\sigma$	$3\sigma$
$\Psi$	$68.2\%$	$95.4\%$	$99.7\%$

$\Psi$	$90\%$	$95\%$	$99\%$
e	$1.64\sigma$	$1.96\sigma$	$2.58\sigma$