{"id":2401,"date":"2015-06-25T19:02:48","date_gmt":"2015-06-25T18:02:48","guid":{"rendered":"http:\/\/roboblog.fatal-fury.de\/?p=2401"},"modified":"2018-12-27T10:41:56","modified_gmt":"2018-12-27T09:41:56","slug":"warum-wird-bei-der-varianz-durch-n-1-geteilt","status":"publish","type":"post","link":"http:\/\/roboblog.fatal-fury.de\/?p=2401","title":{"rendered":"Warum wird bei der Varianz durch n-1 geteilt?"},"content":{"rendered":"<p>Warum wird bei der Varianz durch n-1 geteilt?<br \/>\nGoogle bietet bestimmt eine f\u00fclle an Antworten. Hier ist noch eine:<\/p>\n<blockquote><p>1\/(n-1) * SUM_i=1,n(xi-xavg)^2<br \/>\nMan teilt durch die Anzahl der Freiheitsgerade. L\u00e4sst man das Quadrat in der Summe weg, so ergibt die Summe 0. Der n-te Term ist gleich minus der Summe der vorherigen Terme. Dadurch ist der n-te Term eindeutig festgelegt. Der Freiheitsgrad betr\u00e4gt nur noch n-1<\/p><\/blockquote>\n<p>Update 12.2018<br \/>\nDas nennt sich wohl <a href=\"https:\/\/en.wikipedia.org\/wiki\/Bessel%27s_correction\">Bessel's correction<\/a><\/p>\n<blockquote><p>In statistics, Bessel's correction is the use of n ? 1 instead of n in the formula for the sample variance and sample standard deviation, where n is the number of observations in a sample. This method corrects the bias in the estimation of the population variance. It also partially corrects the bias in the estimation of the population standard deviation. However, the correction often increases the mean squared error in these estimations. This technique is named after Friedrich Bessel. <\/p><\/blockquote>\n","protected":false},"excerpt":{"rendered":"<p>Warum wird bei der Varianz durch n-1 geteilt? Google bietet bestimmt eine f\u00fclle an Antworten. Hier ist noch eine: 1\/(n-1) * SUM_i=1,n(xi-xavg)^2 Man teilt durch die Anzahl der Freiheitsgerade. L\u00e4sst man das Quadrat in der Summe weg, so ergibt die Summe 0. Der n-te Term ist gleich minus der Summe der vorherigen Terme. Dadurch ist [&hellip;]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4],"tags":[35],"class_list":["post-2401","post","type-post","status-publish","format-standard","hentry","category-allgemein","tag-math"],"_links":{"self":[{"href":"http:\/\/roboblog.fatal-fury.de\/index.php?rest_route=\/wp\/v2\/posts\/2401","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/roboblog.fatal-fury.de\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/roboblog.fatal-fury.de\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/roboblog.fatal-fury.de\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"http:\/\/roboblog.fatal-fury.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=2401"}],"version-history":[{"count":3,"href":"http:\/\/roboblog.fatal-fury.de\/index.php?rest_route=\/wp\/v2\/posts\/2401\/revisions"}],"predecessor-version":[{"id":3881,"href":"http:\/\/roboblog.fatal-fury.de\/index.php?rest_route=\/wp\/v2\/posts\/2401\/revisions\/3881"}],"wp:attachment":[{"href":"http:\/\/roboblog.fatal-fury.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2401"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/roboblog.fatal-fury.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=2401"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/roboblog.fatal-fury.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=2401"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}