Say that we make an experiment where we want to see the effect of different fertilizers on corn yield. The data from this experiment is recorded in a spreadsheet, where the variable "yield" is the continuous response variable and the different treatments are recorded with numeric labels (i.e., the variable "treatment" is equal to 1, 2, 3, or 4). When performing an analysis of variance for these data, what is the right way of converting the variable "treatment" into a factor and of running this a