Nelson rules

Rule 1

One point is more than 3 standard deviations from the mean.

Rule 2

Nine (or more) points in a row are on the same side of the mean.

Rule 3

Six (or more) points in a row are continually increasing (or decreasing).

Rule 4

Fourteen (or more) points in a row alternate in direction, increasing then decreasing.

Rule 5

Two (or three) out of three points in a row are more than 2 standard deviations from the mean in the same direction.

Rule 6

Four (or five) out of five points in a row are more than 1 standard deviation from the mean in the same direction.

Rule 7

Fifteen points in a row are all within 1 standard deviation of the mean on either side of the mean.

Rule 8

Eight points in a row exist with none within 1 standard deviation of the mean and the points are in both directions from the mean.