A psychologist examines six personality tests. She suspects that four of the tests are really measuring the same personality trait and that the other two measure another personality trait. What kind of research should the psychologist conduct to test her hypothesis?

A) A field study
B) A case study
C) Factor analysis
D) Idiographic research

Factor analysis is a statistical technique used to identify patterns in data and determine the underlying structure of a set of variables. In this case, the psychologist can use factor analysis to examine the correlations between the six personality tests and determine if there are any underlying factors or traits that are being measured. This can help her determine if her hypothesis is correct and if the tests are measuring the same or different personality traits. A field study, case study, or idiographic research would not be appropriate in this situation as they do not involve statistical analysis of the data.