| Z | Area to left | Area to right | Two-Tailed |
| -2.57 | .005 | .995 | .01 |
| -2.33 | .001 | .999 | .002 |
| -1.96 | .025 | .975 | .05 |
| -1.64 | .05 | .95 | .10 |
| 0.00 | .50 | .50 | 0 |
| +1.64 | .95 | .05 | .10 |
| +1.96 | .975 | .025 | .05 |
| +2.33 | .99 | .01 | .02 |
| +2.57 | .995 | .005 | .01 |
Notation: Let zp represent a standard normal value with a left tail area of p, e.g., z.975 = +1.96.