On the Inference about the Mean under Stratified Random Sampling

• Main Author: 李琇玉
• Other Authors: 丁承
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/97440428656372965241

博士 === 國立交通大學 === 經營管理研究所 === 94 === It is of interest to make inference about the mean for a population consisting of different strata. Assuming that prior probabilities of strata and normality of the measure are given, traditional methods require that the equality of within-stratum variances be first examined. If the variances are equal, then use the exact t statistic; otherwise use the approximate t statistic. In this study, we have investigated the necessity of the equal-variance assumption for the exact t statistic by comparing the power of the two t tests. Based on extensive Monte Carlo simulation, it has been found that the equal-variance assumption can be ignored if prior probabilities are equal. In addition, the sample size of 50 is large enough to make the exact t test effective for the problem of inference about the population mean, regardless of the equality of within-stratum variances. A simple procedure has been recommended to facilitate statistical inference. The procedure, illustrated with Taiwan’s inbound tourism expenditure data, is particularly useful for the studies where stratified random sampling is conducted and inference for the mean daily expenditure is desirable. The procedure applies for any type of tourism expenditure during any time period. The resulting information is useful for tourism policy makers, the tourism industry, and tourists.