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In statistics, the Neyman–Pearson lemma, named after Jerzy Neyman and Egon Pearson, states that when performing a hypothesis test between two simple hypotheses ''H''0: ''θ'' = ''θ''0 and ''H''1: ''θ'' = ''θ''1, the likelihood-ratio test which rejects ''H''0 in favour of ''H''1 when : where : is the most powerful test at significance level ''α'' for a threshold η. If the test is most powerful for all , it is said to be uniformly most powerful (UMP) for alternatives in the set . In practice, the likelihood ratio is often used directly to construct tests — see Likelihood-ratio test. However it can also be used to suggest particular test-statistics that might be of interest or to suggest simplified tests — for this, one considers algebraic manipulation of the ratio to see if there are key statistics in it related to the size of the ratio (i.e. whether a large statistic corresponds to a small ratio or to a large one). == Proof == Define the rejection region of the null hypothesis for the NP test as : where is chosen so that . Any other test will have a different rejection region that we define as . Furthermore, define the probability of the data falling in region R, given parameter as : For the test with critical region to have level , it must be true that , hence : It will be useful to break these down into integrals over distinct regions: : and : Setting , these two expressions and the above inequality yield that : Comparing the powers of the two tests, and , one can see that : Now by the definition of , : : Hence the inequality holds. 抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)』 ■ウィキペディアで「Neyman–Pearson lemma」の詳細全文を読む スポンサード リンク
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