Which procedure would increase the validity of the conclusions from this experiment?

Types of procedures that could increase the validity of conclusions from experiements are ...

Single-blind procedures - the subject does not know which treatment they receive

Double Blind procedures - neither the experiementer or the subject know the treatments they receive

matched pairs experiements - used in experimental research in order for different experimental conditions to be observed while being able to control for individual difference by matching similar subjects or groups with each other.

experiments with a control and lots of trials and so fourth!

-Increasing the number of times the activity is repeated

-Repeating the experiment makes it less likely that wrong conclusions will be made due to random variation.