Test set: Difference between revisions

Test set (edit)

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 ==How precise is the estimate of R<sub>free</sub> for a certain number of test set reflections?==
-The estimate for the relative error of [[iucr:Free_R_factor|R<sub>free</sub>]] is 1/sqrt(n), where n is the size of the test set. So if n is 1000, and the [[iucr:Free_R_factor|R<sub>free</sub>]] is 31%, you would expect its relative error to be 31%/sqrt(1000), which is about 1%.
+The estimate for the relative error of [[iucr:Free_R_factor|R<sub>free</sub>]] is 1/sqrt(2n), where n is the size of the test set (Tickle et al., Acta Cryst. (2000) D56 , 442-450). So if n is 1000, and the [[iucr:Free_R_factor|R<sub>free</sub>]] is 31%, you would expect its relative error to be 31%/sqrt(2000), which is about 0.7%.
 I believe this is from a paper of Ian Tickle (FIXME: reference).