A psychologist wishes to estimate the level of depression of patients that seek
outpatient psychotherapy. She decides to select her sample from ten outpatient
clinics that have at least 50 patients in each clinic. She randomly selects six patients
from each clinic and administers a test that measures depression on a quantitative
scale. Consider the following propositions: Proposition I: If this study is carefully
performed twice, we are guaranteed to sample the same subjects. Proposition II: If
this study is performed twice, we are guaranteed to observe exactly the same
depression scores, as long as there are no mistakes in calculation or data entry.