Suppose you wanted to conduct a study to see if depressed individuals bite their nails more than non-depressed individuals. Which of the following would be the best way to proceed?

(a) Measure participants’ depression with a questionnaire and ask them to give a rating of how much they bite their nails. Then classify participants as ‘depressed’

or ‘non-depressed’ on the basis of their questionnaire scores. We could then see if there was a difference in how much they bit their nails

(b) As per

(a) above but don’t divide the participants into two groups; use actual depression scores in the analyses and see if there is a relationship between depression and biting nails

(c) This sort of study is impossible to carry out and so we couldn’t proceed with it

(d) None of the above