Standard Normal Landmarks

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.