Statistics and Probability Choose the study design that best matches each statement described below. The study design may be used more than once or none at all. (24 points) Statement Study Design Blinding or masking is used to control potential bias. A. Case-Control Observational epidemiological studies, this design is A. Cross-Sectional cheaper and faster to conduct because of the usage of already existing data. Control groups can have old or standard treatment or A. Ecological placebo. Data on exposure and outcome at the individual level A. Prospective Cohort is gathered at one point in time. Disease-free individuals are enrolled based on a A. Retrospective Cohort defined population or exposure at the present then followed up over time to see who develops the disease of interest. Efficient for multiple exposures. A. Randomized Clinical Trial Efficient for multiple outcomes. Efficient for rare outcomes, with exposure ascertained before the outcome. For each case recruited into the study, a sex- and age- matched control was recruited. Observational study with greater potential for loss-to- follow up. Have the highest internal validity. Inexpensive study that can be quickly conducted when individual level data are not available.Less expensive design useful for diseases that are prevalent and of long duration. Preferred when the variability of exposure in the group is low or the variability of exposure between groups is high. Randomization after enrollment confirms that participants have equal probability in being in exposed or unexposed groups. Subjects are enrolled with and without the outcome of interest to evaluate if they were exposed in the past