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
A sample is a subset of the population, selected so as to be representative of the larger population. All of the following are TRUE about cluster sampling, EXCEPT: 
Select and explain. 
A. Sample size is same as that of simple random sampling, B. It is a two stage sampling, C. It is cheaper than other methods of sampling, D. It has the disadvantage of higher sampling error
A: Sample size is same as that of simple random sampling
Answer: A: Sample size is same as that of simple random sampling 
Explanation: A cluster random sample results from a two-stage process in which the population is divided into clusters and a subset of the clusters is randomly selected. Cluster sampling is somewhat less efficient than the other sampling methods because it requires a larger sample size. The recommended way to select a simple random sample is to use a table of random numbers or a computer-generated list of random numbers. So that the sample size is not same as that of cluster random sampling. Ref: Dawson B., Trapp R.G. (2004). Chapter 4. Probability & Related Topics for Making Inferences About Data. In B. Dawson, R.G. Trapp (Eds), Basic & Clinical Biostatistics, 4e.