{"knowledge_schema": {"broad_category": "Statistics \u2192 Hypothesis Testing \u2192 Comparing Groups", "refinement": "This problem involves determining whether two different microbial cell types exhibit significantly different responses to a stressor over time, specifically at their extinction points.", "specific_scope": "The focus is on analyzing the optical density data of the two microbial cell types to assess their extinction points under a specific stressor, using appropriate statistical tests based on the data's distribution.", "goal": "To ensure that the extinction points of the two microbial cell types are significantly different, using the correct statistical methods based on the normality of the data."}, "summary": "To determine if the extinction points of two different microbial cell types under a stressor are significantly different, you need to analyze the optical density data. First, check the normality of the data. If the data is normal, you can use an unpaired t-test; if not, use the Wilcoxon rank-sum test. This approach ensures that you apply the appropriate statistical test based on the data's distribution, allowing for a valid comparison of the extinction points."}