一直在思考在對數據進行處理時，對數化比如 log2或者是log10處理的目的，感覺下面的說法很有道理：
Log transformation is just one way to make the skewed distribution less skewed. For parametric statistical methods,
it helps to satisfy the assumption of inferential statistics. For non-parametric methods, it does not matter if the data
is skewed or not. Log is not the only way to make the transformation, box-cox method could help you find the best
transformation for your data. however log is indeed the most powerful one.