Department Colloquium
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Speaker:
Jessica Kohlschmidt Department of Statistics The Ohio State University Time and Place: 3:30 p.m., Friday, February 1, 2008, 14 Allen Title: Ranked Set Sampling: An Alternative to Simple Random Sampling Abstract: Simple random sampling (SRS) is widely used for sampling purposes. We will discuss SRS and some of the variations that are accepted methods of sampling. I will present an alternative sampling method: ranked set sampling (RSS). RSS has been receiving considerable attention in the statistics literature. Researchers have shown that ranked set sampling outperforms simple random sampling in many situations by reducing the variance of a parameter estimator, thereby providing the same accuracy with a smaller sample size than is needed in simple random sampling. Ranked set sampling involves preliminary ranking of potential sample units on the variable of interest using judgment or an auxiliary variable to aid in sample selection. I will describe the various forms of RSS. We will discuss some advantages and disadvantages to using this ranking procedure. In some situations, RSS may be of more use if we select units in a fashion that is unbalanced for each group. RSS is thought to have the most impact on sampling when the cost of actually collecting measurements on the variable of interest for each individual is costly. If we can use ranking to reduce the number of units needed in the sample, then we can save considerable time and money in the process of sampling. Refreshments: 3:00 p.m., 467 Allen |