Question

Your best friend frequently suffers from severe headaches. You’ve noticed that your friend consumes a great deal of diet cola, and so you consider the hypothesis that the artificial sweetener in the cola is responsible for the headaches. Devise a way to test your hypothesis using a single case design. What do you expect to find if your hypothesis is correct? If you obtain the expected results, what do you conclude about the effect of the artificial sweetener on headaches?

(There is no actual case study, you're supposed to design a fake way to test the hypothesis...)

Answer 1

Hypothesis: Artificial sweetener in the cola is responsible for the headaches.

To test this hypothesis using a single case design, I would ask my friend to check whether the headache comes after drinking cola every time for a period of 1-2 weeks. I would ask her to maintain a record whenever the headache succeeds drinking cola. I would also ask her to keep a check if anything else that she is consuming which may be leading to her severe headahes.

If I obtain the result that headache most of the time is succeeded after having cola, I would conclude the artificial sweetener in the cola is not suiting my friend and results in headache.

However for a generalized conclusion, a study can be done a larger sample to test if the artificial sweetener in the cola really impacts the health.