The melt flow index (MFI) of commercial polystyrene samples has been investigated throughout an interlaboratory comparison study. The homogeneity samples have been assessed prior to the distribution over the participants. The one-factor analysis of variance model has been applied to separate and evaluate the uncertainty components arising from the analytical method and the heterogeneity of the samples. It has been shown that the samples are sufficiently homogenous. The stability of the samples has been monitored over 6 months. The stability and the uncertainty arising from the instability of the samples have been evaluated throughout the linear regression analysis. No significant trend could be detected over the stability assessment period. The results reported by the participants have been investigated. An almost normal distribution shape has been obtained with no evidence for outlier or systematic bias. The MFI value has been evaluated as consensus value from the results reported by the participants with a standard combined uncertainty of ~ 2.2%.

在整个实验室间的比较研究中，已经对商品聚苯乙烯样品的熔体流动指数（MFI）进行了研究。在分配给参与者之前，已经对同质性样本进行了评估。采用单因素方差分析模型来分离和评估由分析方法和样品的异质性引起的不确定性成分。已经显示出样品足够均匀。样品的稳定性已经监测了6个月以上。在整个线性回归分析中，都对样品的稳定性和不确定性进行了评估。在稳定性评估期间未发现明显趋势。参与者报告的结果已经过调查。已获得几乎正态分布的形状，没有证据表明存在异常或系统性偏差。根据参与者报告的结果，将MFI值评估为共识值，标准综合不确定度约为2.2％。