Specify whether Minitab displays a time series plot.
Residual
Plots
Select individual plots or have Minitab display all four plots in one graph.
ACF of
residuals: Display the autocorrelation function (ACF) for the residuals. Use this plot to verify that the residuals are not correlated. The presence of autocorrelated residuals indicates that you may need to modify the model terms.
PACF of
residuals: Display the partial autocorrelation function (PACF) for the residuals. Use this plot to verify that the residuals are not correlated. The presence of autocorrelated residuals indicates that you may need to modify the model terms.
Individual
plots: Select the residual plots that you want to display.
Histogram of
residuals
Display the shape and spread of the residuals. Use the histogram of residuals to determine whether the data are skewed or whether outliers exist in the data.
Normal plot of
residuals
Display a normal probability plot of the residuals. Use the normal plot of residuals to determine whether the residuals are normally distributed.
Residuals versus
fits
Display the residuals versus the fitted values. Use the residuals versus fits plot to determine whether the residuals are unbiased and have a constant variance.
Residuals versus
order
Display the residuals versus the order of the data. The row number for each data point is shown on the x-axis. Use the residuals versus order plot to see how accurate the fitted values are compared to the observed values during the observation period.
Four in one: Display all four residual plots together in one graph.
Residuals versus the
variables
Enter one or more variables to plot versus the residuals. Use the residuals versus the variables plot to assess whether a variable that is not in the analysis systematically affects the response.
