One problem with this hypothesis is that the theory is most likely based on a biased opinion of the student.
The theory is too general. It does not take into account that some people may not like, or care much about, white chocolate. If they don't like it, eating it will not make them happier.
The hypothesis also does not give any reason on why the white chocolate will make other people happier. It just assumes that it will because it's chocolate.
Another problem is that there is no way to test this theory and get conclusive results.
It would be difficult to calculate the results because many factors contribute to the amount of happiness a person feels in a certain situation.
To prove this theory, you would have to make sure that all the people you test have the same background, the same health and mental conditions, the same views on white chocolate, and make sure that they went through the same situations, prior to and following eating the chocolate (with equal reactions to those situations).
That's impossible to control. Furthermore, controlling these factors would destroy the point of the hypothesis because all people are different.
A better hypothesis that the student can test would be: People who love white chocolate will be happier after eating it.
