Fleiss J L, Turgeon L, Chilton N W, Listgarten M A
Division of Biostatistics, Columbia University School of Public Health, New York, NY.
J Periodontol. 1990 Apr;61(4):201-5. doi: 10.1902/jop.1990.61.4.201.
Various statistical properties of the plaque index, the gingival index, and the whole-mouth averages of pocket depth and attachment level measurements were examined using data from a 4-year randomized trial of 80 patients with a history of treated periodontal disease. Departures from normality were assessed by the median of the standardized distribution, by the coefficients of skewness and kurtosis, and by the Kolmogorov goodness-of-fit test. The relative precisions of probing pocket depth and of attachment level were measured, as were correlations between repeated measurements over time for the four clinical measures. The distribution of the plaque index was far from normal, but the distribution of its logarithm was more nearly normal. The distributions of the other clinical measures were effectively normal to varying degrees of approximation. With only rare exceptions, correlations between repeated measurements on the same clinical variable remained relatively constant no matter how far apart in time the measurements were made, at least up to 4 years. The whole-mouth mean of the attachment level measurements seemed to be relatively more precise than the whole-mouth mean of the pocket depth measurements.
利用一项针对80例有牙周病治疗史患者的4年随机试验数据，对菌斑指数、牙龈指数以及全口平均牙周袋深度和附着水平测量值的各种统计特性进行了研究。通过标准化分布的中位数、偏度和峰度系数以及柯尔莫哥洛夫拟合优度检验来评估数据是否偏离正态分布。测量了探诊牙周袋深度和附着水平的相对精度，以及这四项临床指标随时间重复测量之间的相关性。菌斑指数的分布远非正态分布，但其对数分布更接近正态分布。其他临床指标的分布在不同程度上有效地近似于正态分布。除极少数例外情况外，无论两次测量在时间上相隔多久（至少长达4年），同一临床变量重复测量之间的相关性都保持相对稳定。附着水平测量值的全口均值似乎比牙周袋深度测量值的全口均值相对更精确。
