This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Epidemiology, Subject name: Social & Preventive Medicine
[{'content': 'The correlation coefficient between two variables x and y of -0.99 shows \nSelect and explain. \nA. No association, B. Weak association, C. Strong association, D. None of the above', 'role': 'user'}, {'content': "Answer: C \nExplanation: Correlation coefficients are used in statistics to measure how strong a relationship is between two variables. Pearson's correlation is a correlation coefficient commonly used in linear regression. Correlation coefficient formulas are used to find how strong a relationship is between data. The formulas return a value between -1 and 1, where:1 indicates a strong positive relationship.-1 indicates a strong negative relationship.A result of zero indicates no relationship at all", 'role': 'assistant'}]