Residuals button: displays the scatter plot of residuals, including the result of the Durbin-Watson test. Below are typical values for the Durbin-Watson test and the corresponding residual scatter plot.
1. Positive autocorrelation of residuals (DW test almost or equal to 0.0)
Residuals of the same sign cluster together. If a residual is positive, the next one is very likely to be positive as well, creating a "wavy" or "cyclical" pattern. See the example below, resulting from fitting function number 17 to the dataset "DW test almost 0 (function n. 17).txt":
2. No Autocorrelation of residuals (DW test close or equal to 2.0)
The residuals are completely independent. Knowing the sign of a residual makes it impossible to predict the sign of the next one. See the example below, resulting from fitting function number 11 to the dataset "DW test close to 2 (function n. 11).txt":
3. Negative Autocorrelation of residuals (DW test almost or equal to 4.0)
Residuals constantly alternate signs. A positive residual is immediately followed by a negative one, and vice versa. See the example below, resulting from fitting function number 6 to the dataset "DW test almost 4 (function n. 6).txt":
Note: DW values between 1.5 and 2.5 are generally considered "acceptable" or "normal" in curve fitting, presenting no cause for concern. For values significantly outside this range, the curve fit should be critically evaluated and the causes identified.