”We used principal component (PC) analysis to identify and remove outlier
samples. We converted each sample into a z score statistic, based on the
squared distance of its 1st PC from the population mean. The z statistic
was converted to a false-discovery rate with the Gaussian cumulative
distribution and the Benjamini-Hochberg procedure (Benjamini and Hochberg,
1995). Samples falling below an FDR of 0.2 were designated at outliers and
removed. This filtering procedure was performed iteratively until no samples
were determined to be an outlier. A total of 24 samples were removed in this
manner.“ 这是一篇文章中介绍的方法， 这里的 转成fdr的 z statistic 是指什么，谁能给说一下这个分析的大体步骤，急用谢谢各位了。
sample1 sample2 ...
gene1 0.4 0.3 ...
gene2 ... ... ...
...
