# Math Help - normal distribution to approximate

1. ## normal distribution to approximate

How do I find $P(Z \le -0.9)$? I think it is the same as $P(Z \ge 0.9)$. So then, do I just find $\Phi$0.9 and subtract it from 1? (1-0.8159=0.1841)

2. I really like these online stat calculators.
They give p-values and they have all kinds of densities, t, F...
Free Cumulative Area Under the Standard Normal Curve Calculator
Plugging in -.9 give a probability of .1840601 and you can see a pretty picture too.

3. Thank you so much! That calculator definitely will come in handy.

4. Notice that there are many different distributions on the home page.
Also when you learn about p-values you will look back and really appreciate my comments today.