You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is To test the association between risk factor and disease, which of the following is the wakest study design - and explain in detail?
Ans. is 'b' i.e., Ecological study To test the association between risk factor and diseaseo Most reliable, overall --> systematic review and meta-analysis of RCTso Most reliable individual study --> Randomized controlled trial.o Most reliable observational analytic study Coho studyo Least reliable study and least reliable observational analytic study --> Ecological study.