Standard normal distribution
Click anywhere on the curve to drop a point, or type a z-score directly. The shaded area is the p-value for the test you pick below.
The dark line marks your z-score; the shaded region is the area the p-value refers to
Drag the point left and right, click anywhere on the curve, or edit the z-score field above — all three stay in sync.
| α | One-tailed z | Two-tailed z |
|---|---|---|
| .10 | 1.282 | 1.645 |
| .05 | 1.645 | 1.960 |
| .01 | 2.326 | 2.576 |
These are the z-scores that make p exactly equal to α for that kind of test — try typing one into the box above.