Adjust for pretreatment differences

## Warning: A numeric `legend.position` argument in `theme()` was deprecated in ggplot2
## 3.5.0.
## ℹ Please use the `legend.position.inside` argument of `theme()` instead.
## This warning is displayed once every 8 hours.
## Call `lifecycle::last_lifecycle_warnings()` to see where this warning was
## generated.

## Effect:  9.73256615797477

• Important when there is an imbalance between groups

• Good analysis will include clear explanations of any adjustments