Find area under the curve of a standard normal distribution Given a standard normal distribution, how can I find the
area under the curve that lies:
1. to the left of z = −1.39;
2. to the right of z = 1.96;
3. between z = −2.16 and z = −0.65;

The areas for one, two, and three standard deviations about the mean are well known, as .68, .95, .997 roughly. But in general, there's no way to find the area under the standard normal distribution without using a computer, calculator, or a chart. 
edit1: most charts will give the area to the left of a given $z$-score. To find other values, use symmetry and complements. For example,
$\operatorname{Pr}(Z > -.5) = 1 - \operatorname{Pr}(Z < -.5)$
and 
$\operatorname{Pr}(Z < - 1) = \operatorname{Pr}(Z > 1)$
edit2: I'm not careful above about whether to use "$\ge$" or "$>$" because the answers will always be the same for a continuous distribution like a normal distribution. Be careful you don't switch them around for discrete distributions because then it will affect the answer.
