independent and dependent variable

a Study found that people rated cartoons as funnier when holding a pen in their teeth (which forced them to smile) than when holding a pen in their lips (which forced them to frown). For this study, identify the independent variable and the dependent variable.

am I correct because I am confused.


Independent variable - Pen in teeth and holding a pen in their lips
Dependent variable – rated cartoons funnier

That's sort of a funny problem. Anyway, yes, the independent variable is the pen placement; the cartoon was funnier BECAUSE they had a pen in their teeth. It's a cause and effect thing. The pen was in their teeth which caused the cartoon to be funnier, ie, the funniest of the cartoon depended on where the pen was held.