Dr. vockler conducted an experimental study to determine if different dieting programs had any impact on weight loss. in this context, weight loss would be the study's:

I believe the answer is: Dependent variable

Dependent variable refers to the variable that would be influenced by other variables. In research, dependent variable represent the things that the researchers want to study and find out whether it would be influenced by a certain things or not.

this null effect is caused by a weak manipulation and ineffective internal validity. in a scientific study, as the one dr. morimoto is trying to perfom, internal validity refers to the confidence placed in the cause-effect relationship and to how well an experiment is done and able to eliminate confounding variables.