Answer:
The weakest of all scientific findings are given by case studies.
Explanation:
Case studies are observational or descriptive studies focalized on the analysis of a particular object (an individual, place, event, etc.) in a specific situation. Beacuse of its descriptive nature, it does not provides information about cause-effect relationships and does not consider the effect of random variations. It is the weakest of all scientific findings.
Correlational studies involves measurements of at least two different variables and try to identify if there is a specific relationship between variables, it means if there is a specific trend in the variation of one variable as a response to the variation in the other one (for example, when the temperature of a given solution increases, the solubility of the solute also increase). Although this kind of studies does not provides information about cause relationships, the trend between variables are well stated.
Experimental studies are the ones in which a researcher makes sure of providing a controled environment and manipulates a particular variable to see responses of one or more different variables. These studies provides well supported information.
Epidemiological studies the purpose to analyze all the factors involved in an epidemic (causes, incidence, evolution, etc.). It includes observational and experimental studies that complement each other. Because of the importance of these reasearch on public health, their scientific findings are well stablished and supported.
Summarizing, the weakest of all scientific findings are provided by case studies.