what is the first known data type when did the term covariate come from how does the term variable come from what is the first covariate used for where does the term covariate come from where does the term correlation come from when was the first known covariate used when was the term covariate first used what the term covariate comes from where did the term variable come from what year does the term covariate come from when was the first covariate defined what is the first covariate where does the term covariate come from? quizlet where did a covariate come from when did a covariate come from what is the first time a statistical study used a variable? where does the term covariate come from where does the term covariates come from? define covariate