Survey About Happiness

When I did a survey about the happiness I found it a very good survey. I was in a good mood when I did it, so in the beginning I thinked its a good tools. But I think if i was in a different mood it will not be a good tools.I think if the survey was in the exams time for sure the answer will be different, because the survey was asking about one week before the survey. I think if the person who want to make a study about happiness, he should mix the groups and ask some students, workers and perents, because I think that will give a true results!