The phrase "grouping factor" is correct and usable in written English.
It is typically used to refer to a factor that influences the assembly of a group of individuals or items into different categories or sets. For example, "The teacher used age as the grouping factor for her students."
In fitting the models to the data, heteroscedasticity was modelled as a power function of the absolute values of cambial age, while a first-order autoregressive correlation structure AR(1) was applied to model correlation among observations at successive cambial ages within each grouping factor.
Discriminant function analyses (DFA) were performed using shape variables as the dependent factors and habitat type as the grouping factor.
However, a substantial portion of BBS observers conducted surveys on >1 BBS route, causing the grouping factor of observer to lose the nesting property.
All data were analysed by one-way ANOVA with the salt concentration as the grouping factor.
Secondary efficacy parameters and laboratory variables were analyzed using ANOVA with treatment as a grouping factor.
In this essay, the fifteen organizations were treated as a grouping factor.
Individual donor organizations enter the analysis as a grouping factor that represents unobserved organizational effects.
2) Model 2: The grouping factor (i.e. binary variable) was added into Model 1 as a second predictor variable 3) Model 3: The interaction (i.e. grouping factor by total) was added into Model 2 as the third predictor variable.
Notice that when a repeated measures ANOVA with no grouping factor is applied, its SS error term contains both the group-by-occasion interaction term and the residual error from the repeated measures ANOVA with a grouping factor.
Again, IPGRIP was the call variable with the highest power of discrimination for genotype as a grouping factor.
In a mixed effects model, at least one of these covariates is categorical and represents a grouping factor.
