A hypothesis is an educated guess or proposition made as a basis for reasoning or research without any assumption of its truth. It's testable and falsifiable statement about two or more variables related in some way.
This is what you measure in an experiment and what changes when you change the independent variable - like how much you enjoy the movie after watching it.
This is a group in an experiment that does not receive the treatment or test variable. It's like your friend who didn't watch any movie but still rates their evening.