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': 'Power of a study can be increased by- \nSelect and explain. \nA. Increasing a error, B. Decreasing ss error, C. Decreasing a error, D. Increasing ss error', 'role': 'user'}, {'content': 'Answer: B \nExplanation: <p> Decreasing ss error. Reference:Simple Biostatistics by Indrayan & Indrayan,1stbedition,page no: <\\p>', 'role': 'assistant'}]