The effect of subsampling sites within patients.
The effect of subsampling sites within patients.
复制标题
患者体内二次采样部位的影响。
DOI：
10.1111/j.1600-0765.1985.tb00415.x
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发表时间：
1985
影响因子：
3.5
通讯作者：
L. Laster
中科院分区：
文献类型：
--
作者：
L. Laster
In recent periodontal research, multiple sites within patients have been utilized as the primary observations or sampling units. In the present study a simple approach for the single sample case was used to demonstrate the effect of site-specific analyses when the patient is not treated as the sampling unit. This approach was shown to underestimate the variance of the mean value in question and thus, in tests of hypotheses concerning the mean, lowers artificially the p-level or equivalently raises artificially the 1-α confidence level of intervals.
The error introduced by this procedure increased when the number of actual primary random sampling units (the patients) was small, for this resulted in inappropriately lowered Student's tvalues. The error also increased as the number of sites used within patients increased and decreased slightly as the number of patients increased. From only six periodontal patients where six randomly chosen sites were observed for pocket depth in mm, a statistically significant (p<0.01) intraclass correlation was seen (ϱ1=0.31). If the 36 sites had been treated as independently distributed, a true probability of p(true)=0.27 would have been misread nominally as p(nominal)=0.05.
临床牙周试验数据分析统计方法的比较。
影响因子：
6.7
作者：
Haffajee,AD;Socransky,SS;Lindhe,J
通讯作者：
Lindhe,J