This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Normal Distribution, Skewed Distributions, Subject name: Social & Preventive Medicine
[{'content': 'Variation of Sample mean from Population mean is: \nSelect and explain. \nA. Standard error of the mean, B. Standard error of propoion, C. Standard error of difference between two means, D. Standard error of difference between two propoions', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Standard error: It is the variation of sample mean from population mean. Sample mean is known as statistic. Population mean is known as parameter. - Standard detion is the variation in a single value from the mean of a sample.', 'role': 'assistant'}]