This paper, comparison of two sample tests, is motivated by the fact that in the test of significant difference between two independent samples, numerous methods can be adopted;each may lead to significant different r...This paper, comparison of two sample tests, is motivated by the fact that in the test of significant difference between two independent samples, numerous methods can be adopted;each may lead to significant different results;this implies that wrong choice of test statistic could lead to erroneous conclusion. To prevent misleading information, there is a need for proper investigation of some selected methods for test of significant difference between variables/subjects most especially, independent samples. The paper examines the efficiency and sensitivity of four test statistics to ascertain which test performs better. Based on the results, the relative efficiency favours median test as being more efficient than modified median test for both symmetric and asymmetric distributions. In terms of power of test, median test is more sensitive than Modified Median (MMED) test since it has higher power irrespective of the sample sizes for both symmetric and asymmetric distribution. In terms of relative efficiency for asymmetric distribution Modified Mann-Whitney U test is more efficient than Mann-Whitney U test (MMWU), and then for symmetric distribution, Mann-Whitney U test (MMWU) is more efficient than Modified Mann-Whitney in sample size of 5;but for other sample sizes considered Modified Mann-Whitney U test (MMWU) is better than Mann-Whitney. Using power of test for both symmetric and asymmetric distributions, Mann-Whitney is more sensitive than Modified Mann-Whitney U test (MMWU) because it has higher power.展开更多
In the era of big data,traditional statistical inference methods are faced with great challenges.Taking the two-sample distribution test scenario of big data as an example,this paper proposes the BB-KS test based on m...In the era of big data,traditional statistical inference methods are faced with great challenges.Taking the two-sample distribution test scenario of big data as an example,this paper proposes the BB-KS test based on m out of n bootstrap for solving a single-machine memory and computing constraints.It is verified to the feasibility and effectiveness of the proposed test method through theoretical analysis and numerical simulation.The results show that the BB-KS test can improve the calculation efficiency of the test to a certain extent in the single machine scenario.展开更多
We propose a two-sample test for the mean functions of functional data when the number of bases is much lager than the sample size.The novel test is based on U-statistics which avoids estimating the covariance operato...We propose a two-sample test for the mean functions of functional data when the number of bases is much lager than the sample size.The novel test is based on U-statistics which avoids estimating the covariance operator accurately under the high dimensional situation.We further prove the asymptotic normality of our test statistic under both null hypothesis and a local alternative hypothesis.An extensive simulation study is presented which shows that the proposed test works well in comparison with several other methods under the high dimensional situation.An application to egg-laying trajectories of Mediterranean fruit flies data set demonstrates the applicability of the method.展开更多
An accurate understanding of the intergenerational transmission of income gap is the foundation for theoretical research and policy formulation to address this issue. This paper has employed the method of two sample i...An accurate understanding of the intergenerational transmission of income gap is the foundation for theoretical research and policy formulation to address this issue. This paper has employed the method of two sample instrumental variables to effectively integrate CHIP data and CFPS data and correct the temporal income bias, life-cycle bias and coresidence bias, which are common problems in existing studies, and investigated the tendencies of intergenerational transmission of income gap for China's urban and rural households between 2002 and 2012. Results of empirical study indicate that the intergenerational transmission of income gap for China's urban and rural households has been on the decline yet the level of intergenerational transmission is greater for urban residents than for rural residents. This level of intergenerational transmission of income gap in China is at a medium international level lower than that of countries like the United States, Brazil and Japan and higher than that of Sweden and Chinese Taiwan. Further analysis of the intergenerational mobility of various income groups suggests the following: the intergenerational solidification of the bottom and top income groups of urban residents has significantly improved, which is the source for the reduction of intergenerational transmission of income gap. Rural residents of bottom income group are vulnerable to falling into the trap of intergenerational transmission of low income. In order to mitigate the intergenerational transmission of income gap, efforts must be made to improve educational allowance policy and increase the opportunities for children from poor and underprivileged families to receive education and to eliminate the divide of labor markets to create equal job opportunities for each and every worker.展开更多
文摘This paper, comparison of two sample tests, is motivated by the fact that in the test of significant difference between two independent samples, numerous methods can be adopted;each may lead to significant different results;this implies that wrong choice of test statistic could lead to erroneous conclusion. To prevent misleading information, there is a need for proper investigation of some selected methods for test of significant difference between variables/subjects most especially, independent samples. The paper examines the efficiency and sensitivity of four test statistics to ascertain which test performs better. Based on the results, the relative efficiency favours median test as being more efficient than modified median test for both symmetric and asymmetric distributions. In terms of power of test, median test is more sensitive than Modified Median (MMED) test since it has higher power irrespective of the sample sizes for both symmetric and asymmetric distribution. In terms of relative efficiency for asymmetric distribution Modified Mann-Whitney U test is more efficient than Mann-Whitney U test (MMWU), and then for symmetric distribution, Mann-Whitney U test (MMWU) is more efficient than Modified Mann-Whitney in sample size of 5;but for other sample sizes considered Modified Mann-Whitney U test (MMWU) is better than Mann-Whitney. Using power of test for both symmetric and asymmetric distributions, Mann-Whitney is more sensitive than Modified Mann-Whitney U test (MMWU) because it has higher power.
文摘In the era of big data,traditional statistical inference methods are faced with great challenges.Taking the two-sample distribution test scenario of big data as an example,this paper proposes the BB-KS test based on m out of n bootstrap for solving a single-machine memory and computing constraints.It is verified to the feasibility and effectiveness of the proposed test method through theoretical analysis and numerical simulation.The results show that the BB-KS test can improve the calculation efficiency of the test to a certain extent in the single machine scenario.
基金Supported by the National Natural Science Foundation of China(Grant Nos.11671268 and 12271370)the Guangdong Basic and Applied Basic Research Foundation(Grant No.2020A1515010821)+1 种基金the Fundamental Research Funds for the Central Universities(Grant No.12619624)Supported by the Research Start-up Fund for new young Teachers of Capital University of Economics and Business(Grant No.00592254417068)。
文摘We propose a two-sample test for the mean functions of functional data when the number of bases is much lager than the sample size.The novel test is based on U-statistics which avoids estimating the covariance operator accurately under the high dimensional situation.We further prove the asymptotic normality of our test statistic under both null hypothesis and a local alternative hypothesis.An extensive simulation study is presented which shows that the proposed test works well in comparison with several other methods under the high dimensional situation.An application to egg-laying trajectories of Mediterranean fruit flies data set demonstrates the applicability of the method.
基金Project of National Social Sciences Foundation Empirical Study on the Intergenerational Transmission of Income Gap(Grant No.14BJY039)
文摘An accurate understanding of the intergenerational transmission of income gap is the foundation for theoretical research and policy formulation to address this issue. This paper has employed the method of two sample instrumental variables to effectively integrate CHIP data and CFPS data and correct the temporal income bias, life-cycle bias and coresidence bias, which are common problems in existing studies, and investigated the tendencies of intergenerational transmission of income gap for China's urban and rural households between 2002 and 2012. Results of empirical study indicate that the intergenerational transmission of income gap for China's urban and rural households has been on the decline yet the level of intergenerational transmission is greater for urban residents than for rural residents. This level of intergenerational transmission of income gap in China is at a medium international level lower than that of countries like the United States, Brazil and Japan and higher than that of Sweden and Chinese Taiwan. Further analysis of the intergenerational mobility of various income groups suggests the following: the intergenerational solidification of the bottom and top income groups of urban residents has significantly improved, which is the source for the reduction of intergenerational transmission of income gap. Rural residents of bottom income group are vulnerable to falling into the trap of intergenerational transmission of low income. In order to mitigate the intergenerational transmission of income gap, efforts must be made to improve educational allowance policy and increase the opportunities for children from poor and underprivileged families to receive education and to eliminate the divide of labor markets to create equal job opportunities for each and every worker.
