system
Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
When observations are made before and after the exposure to the factor, it is -
assistant
The correct answer is  Ref:Parks 23rd edition pg 852 Tests of significance: Qualitative: Chi- square : 2 or more than 2 groups Mc Nemar test : 1 group. ( before and after intervention) Quantitative: Paired T test: 1 group Student T test/ unpaired T test: 2 groups Anova: more than 2 groups.