This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Biostatistics, Subject name: Social & Preventive Medicine
[{'content': 'All are measures of dispersion around central value except \nSelect and explain. \nA. Mode, B. Variance, C. Standard detion, D. Mean', 'role': 'user'}, {'content': 'Answer: B \nExplanation: The several measures of variation or dispersion of which the following are widely known Range The mean or Average detion The standard detion Ref : Park&;s Textbook of Preventive and Social Medicine; 23rd edition - Pgno. 848', 'role': 'assistant'}]