Stat > Time Series > Single Exp Smoothing > Graphs
Time series plot (including optional forecasts)
Specify whether Minitab displays a time series plot with the predicted data, a plot with the smoothed data, or no plot.
Select individual plots or have Minitab display all four plots in one graph.
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. However, the residuals being normally distributed is not an assumption that has to be met for this analysis.
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.