Deviation-(also known as deviation rate) is to use the ratio relationship between stock price index and moving average to observe the degree of stock price deviation from moving average, so as to determine investors' trading behavior. Deviation rate is called y value for short.

Deviation rate = (current stock price index or stock price -N-day average stock price index or stock price) /n-day average stock price index or stock price × 100

N-day refers to the specific number of days. For example, as published by the Securities News every day, N-day is 6 days and 12 days, which are represented by BIAS(6) and BIAS( 12) respectively.

As can be seen from the formula:

(1) When the stock price is on the moving average, the deviation rate is positive.

⑵ When the stock price is lower than the moving average, the deviation rate is negative.

(3) The farther the stock price is from the moving average, the greater the absolute value of the deviation rate.