This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Social & Preventive Medicine
[{'content': 'Power of study can be increased by \nSelect and explain. \nA. Increasing a error, B. Increasing b error, C. Decreasing a error, D. Decreasing b error', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Power of a Test:\n– Is probability of rejecting a Null hypothesis when a predetermined clinically significant difference is indeed\npresent\n– Measures the ability to demonstrate an association, when one really exists\n– Power of a statistical test: 1 – b ( 1 – probability of Type II error)\n– Power of a statistical test is complimentary to b (probability of Type II error)\n– Power of a statistical test is a numeric representation of: Sensitivity\n– Power of a statistical test can be increased by:\n1. Increasing the no. of subjects in a trial (sample size)\n2. Reducing b (probability of Type II error)\n3. Increasing sensitivity\n– Power of a statistical test is also used for calculation of sample size for a study', 'role': 'assistant'}]