Specify the hold settings for Overlaid Contour Plot

To perform this analysis in Minitab, go to the menu that you used to fit the model, then choose Overlaid Contour Plot > Settings. For more information, go to Stored model overview.

This dialog box varies by the type of model that you used to fit the data.

All model types except general linear models, factorial designs, screening designs, and mixture designs

An overlaid contour plot can include only two continuous variables. If a model has more than two continuous variables, Minitab holds each variable that is not on the plot constant. If a model has categorical variables, Minitab also holds the categorical factors constant.
Hold continuous variables at
Variable
Shows all the continuous variables in your model but not on the plot. This column does not take any input.
Setting
By default, for the continuous variables that are not in the plot, the setting for each variable is its mean. If you want to use a different value, delete the mean value and enter a new value.
Hold categorical variables at
Variable
Shows all the categorical variables in your model. This column does not take any input.
Setting
All categorical variables in the model must be held at a constant value. Select a level at which to hold the variables. The default value is either the lowest numeric value or the first alphabetical value.

General linear models

An overlaid contour plot based on a general linear model can include only two covariates. If a model has more than two covariates, Minitab holds each covariate that is not on the plot constant. If a model has categorical variables, Minitab holds the categorical factors constant.
Hold categorical variables at
Name
Shows all of the categorical variables in your model. This column does not take any input.
Setting
All categorical variables in the model must be held at a constant value. Select a level at which to hold the variables. The default value is either the lowest numeric value or the first alphabetical value.
Hold covariate variables at
Name
Shows all the covariates in your model but not on the plot. This column does not take any input.
Setting
By default, for the covariates that are not in the plot, the setting for each variable is its mean. If you want to use a different value, delete the mean value and enter a new value.

Factorial designs and screening designs

An overlaid contour plot based on a factorial design can include only two continuous factors. If a model has more than two continuous factors, Minitab holds each factor that is not on the plot constant. If a model has categorical factors or covariates, Minitab holds these values constant.
Hold factors at
Variable
Shows all the categorical factors and continuous factors that you controlled in your experimental design but are not on the plot. This column does not take any input.
Setting
All categorical factors in the model must be held at a constant value. Select a level at which to hold the variables. By default, for the continuous factors that are not in the plot, the setting for each variable is its mean. If you want to use a different value, delete the mean value and enter a new value.
Hold covariates at
Variable
Shows all the covariates in your model. Covariates are the continuous variables that you did not control in your experimental design. This column does not take any input.
Setting
All covariates in a factorial design must be held at a constant value. By default, the setting for each covariate is its mean. If you want to use a different value, delete the mean value and enter a new value.

Mixture designs

You can set the holding level for components and process variables that are not in the plot at their highest or lowest settings, or you can set specific levels to hold each. The hold values must be expressed in the units as follows:
  • Components must be in the units as displayed in the worksheet.
  • Process variables must be in coded units.

For more information, go to What is the difference between coded units and uncoded units?.

Note

If your mixture design contains text process variables, you can only set their holding values at one of the text levels.

Hold components at
Lower bound setting
Select to set all components that are not on the plot at their lower bound.
Middle setting
Select to set all components that are not on the plot at their middle setting.
Upper bound setting
Select to set all components that are not on the plot at their highest bound.
Component
Shows all the components in your design but not on the plot. This column does not take any input.
Name
Shows all the components in your design but not on the plot. This column does not take any input.
Setting
Enter a value to hold each component that is not on the plot.
Hold process variables at
Low setting
Select to set process variables that are not on the plot at their lowest setting.
Middle setting
Select to set all process variables that are not on the plot at their middle setting.
High setting
Select to set process variables that are not on the plot at their highest setting.
Process Var.
Shows all the process variables in your design but not on the plot. This column does not take any input.
Name
Shows all the process variables in your design but not on the plot. This column does not take any input.
Setting
Enter a value to hold each process variable that is not on the plot.
Hold mixture amount at
Select a total at which to hold the mixture amount.