Basic BIAS Deviation rate (bias), also known as deviation rate, or y-value for short, is an indicator to reflect the deviation degree between the price and MA in a certain period of time by calculating the percentage difference between the market index or closing price and a moving average, so as to obtain the possibility that the price will reverse or rebound due to deviation from moving average trend in case of severe fluctuation, and that the price will move within the normal fluctuation range Form the credibility of continuing the original potential. The deviation rate is a percentage of the deviation degree (gap rate) between the price and ma. The departure rate curve (bias) is a curve that connects the values of each bias into a line and obtains a wave extension curve with the value of 0 as the horizontal axis.