0 in a study, a variable (= a quantity that can change) that may affect the result of what is being studied:
Onset of marijuana use at a given time point was predicted by the value of each covariate at the time since the previous interview (with the exception of gender, which was a time-constant covariate).
The effect of the intervention was analyzed on the discrepancy scores of post-test minus pretest, with pretest scores serving as a covariate.
The analysis found that there was still a reliable effect of action - outcome delay when response rate was used as a covariate.
When the values of day 14 were used as covariate, no statistically significant difference was obtained between treatments on day 42.
