costs variance 中文意思是什麼
costs variance
解釋
成本差異-
When the covariance matrix formed by securities yields is non - oppositive definite, we provide the model with transaction costs, which risk is variance matrix risk. when the covariance matrix formed by securities yields is not exist, the risk we use is absolute deviation risk and semi - absolute deviation, which is differ with traditional risk such as variance matrix risk or semi - variance matrix risk
在證券收益率協方差陣不一定存在時，給出了不同於以往以證券收益率間的方差或是半方差為風險度量指標而是以絕對離差為風險指標和以半絕對離差為風險指標的含有交易費用的證券組合投資模型。 -
Determining the sample size is crucial for a survey sampling design, for which traditional approaches have to seek some information on population variance or survey costs, however, which may result in either sample size too small and real precision undre desired level, or sample size too large and waste of survey costs
摘要樣本量的確定是抽樣設計中的關鍵問題，傳統方法利用總體方差和調查費用的有關信息來確定樣本量可能產生兩種結果，一種是樣本量過低，無法保證希望的估計精度要求；一種是樣本量過高，導致調查經費的浪費。
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