Internal Pilots for Repeated Measure ANOVA

描述(由申请人提供)：对连续数据的重复测量通常为许多学科的广泛健康研究提供成本和统计敏感性的最佳组合。作为驱动的例子，可以考虑比较显示数字乳房X光照片或放射治疗计划胶片的方法。合格读者的有限数量和成本鼓励选择最小样本量，而科学目标要求对差异非常敏感。准确的样本量分析使科学家能够解决冲突。 不幸的是，准确的样本量选择需要高斯数据的误差方差的精确值。围绕差异的不确定性使内部试点设计非常吸引人。这种设计使用数据的第一部分来估计方差，然后根据需要调整样本大小，以实现目标功率。然而，对于内部飞行员的重复测量，没有合适的分析方法。我们的研究将满足这种新方法的需要。 (1)我们将为重复测量的“单变量方法”(UNIREP ANOVA)开发更好的统计功率近似，包括精确性质和更精确的近似。(2)我们将推导用于UNIREP ANOVA的内部试点设计的最终样本量分布的精确和近似性质。(3)我们将描述UNIREP ANOVA在内部试点设计中的分析性质，包括一些精确和大样本分布，以及实用算法。

DESCRIPTION (provided by applicant): Repeated measures of continuous data often provides the best combination of cost and statistical sensitivity for a wide range of health research in many disciplines. As driving examples, consider comparing methods of displaying digital mammograms, or radiotherapy planning films. The limited number and cost of qualified readers encourage choosing a minimum sample size, while scientific goals demand great sensitivity to differences. An accurate sample size analysis allows the scientist to resolve the conflict. Unfortunately, accurate sample size choice requires an accurate value for error variance of Gaussian data. Uncertainty surrounding the variance makes an Internal Pilot design very appealing. Such designs use the first fraction of the data to estimate the variance and then adjust the sample size up or down, as needed to achieve the target power. However, appropriate analysis methods are not available for repeated measures with internal pilots. Our research will meet the need for such new methods. (1) We will develop better statistical power approximations for the "univariate approach" to repeated measures (UNIREP ANOVA), including exact properties and more accurate approximations.(2) We will derive exact and approximate properties of the distribution of final sample size of Internal Pilot designs used with UNIREP ANOVA.(3) We will describe analytic properties of UNIREP ANOVA in Internal Pilot designs, including some exact and large sample distributions, as well as practical algorithms.