seen from Poland
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seen from United States
seen from Australia
seen from Türkiye
seen from United States
seen from China
seen from United States
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在統計學中，我們感興趣的全部個體或項目所成的集合稱為母體 (population)，譬如，某農場的羊群，某國家的人民。母體的一個未知或已知數值稱為參數 (parameter)，通常用來定義統計模型，譬如，某農場羊寄生蟲的發病率，某國家人均所得變異數。為了估計母體的參數，我們從母體選出一組個體或項目稱為樣本 (sample)。只要不含未知參數，任何一個由樣本數據構成的函數都稱為統計量 (statistic)。所以參數用於母體，而統計量則用於樣本。本文介紹線性代數觀點下的三個基本統計量：樣本平均數 (sample mean)，樣本變異數 (sample variance) 和樣本共變異數 (sample covariance)。
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