﻿{"id":2035,"date":"2013-02-25T21:58:36","date_gmt":"2013-02-25T12:58:36","guid":{"rendered":"http:\/\/fujiitoshiki.com\/improvesociety\/?p=2035"},"modified":"2014-08-11T18:32:26","modified_gmt":"2014-08-11T09:32:26","slug":"why-probability-should-be-converted-to-logarithm-of-logit-in-logistic-regression-analysis","status":"publish","type":"post","link":"https:\/\/www.fujiitoshiki.com\/improvesociety\/?p=2035","title":{"rendered":"Why probability should be converted to logarithm of odds (logit) in logistic regression analysis?"},"content":{"rendered":"<div class=\"theContentWrap-ccc\"><p>In logistic regression analysis, probability is converted to odds, p\/(1-p), and odds is converted to logarithm. Binomial distribution, either event of interest happens or doesn&#8217;t happen, is analysed by multiple regression analysis. <\/p>\n<p>Probability is between 0 and 1. Logarithm of odds (logit) diverges from minus infinity to plus infinity. See charts to understand. <\/p>\n<p>Probability is real between 0 and 1. Take probability horizontal axis and odds vertical axis, respectively. Vertical axis ranges from 0 to infinity, as following chart. <\/p>\n<figure id=\"attachment_2022\" aria-describedby=\"caption-attachment-2022\" style=\"width: 300px\" class=\"wp-caption alignnone\"><a href=\"\/\/fujiitoshiki.com\/improvesociety\/wp-content\/uploads\/Fig1.png\"><img loading=\"lazy\" decoding=\"async\" src=\"\/\/fujiitoshiki.com\/improvesociety\/wp-content\/uploads\/Fig1-300x300.png\" alt=\"Fig1. probability and logit\" width=\"300\" height=\"300\" class=\"size-medium wp-image-2022\" srcset=\"https:\/\/www.fujiitoshiki.com\/improvesociety\/wp-content\/uploads\/Fig1-300x300.png 300w, https:\/\/www.fujiitoshiki.com\/improvesociety\/wp-content\/uploads\/Fig1-150x150.png 150w, https:\/\/www.fujiitoshiki.com\/improvesociety\/wp-content\/uploads\/Fig1.png 303w\" sizes=\"auto, (max-width: 300px) 85vw, 300px\" \/><\/a><figcaption id=\"caption-attachment-2022\" class=\"wp-caption-text\">Fig1. probability and odds<\/figcaption><\/figure>\n<p>Next, take odds horizontal axis and logarithm of odds vertical axis, respectively. Vertical axis ranges from minus infinity to plus infinity as following chart. <\/p>\n<figure id=\"attachment_2027\" aria-describedby=\"caption-attachment-2027\" style=\"width: 300px\" class=\"wp-caption alignnone\"><a href=\"\/\/fujiitoshiki.com\/improvesociety\/wp-content\/uploads\/Fig2.png\"><img loading=\"lazy\" decoding=\"async\" src=\"\/\/fujiitoshiki.com\/improvesociety\/wp-content\/uploads\/Fig2-300x300.png\" alt=\"Fig2. logit and logarithm of logit\" width=\"300\" height=\"300\" class=\"size-medium wp-image-2027\" srcset=\"https:\/\/www.fujiitoshiki.com\/improvesociety\/wp-content\/uploads\/Fig2-300x300.png 300w, https:\/\/www.fujiitoshiki.com\/improvesociety\/wp-content\/uploads\/Fig2-150x150.png 150w, https:\/\/www.fujiitoshiki.com\/improvesociety\/wp-content\/uploads\/Fig2.png 303w\" sizes=\"auto, (max-width: 300px) 85vw, 300px\" \/><\/a><figcaption id=\"caption-attachment-2027\" class=\"wp-caption-text\">Fig2. odds and logarithm of odds (logit)<\/figcaption><\/figure>\n<p>At last, take probability horizontal axis and logit vertical axis, respectively. Although probability ranges only from 0 to 1, logit diverges all real number as following chart. <\/p>\n<figure id=\"attachment_2030\" aria-describedby=\"caption-attachment-2030\" style=\"width: 300px\" class=\"wp-caption alignnone\"><a href=\"\/\/fujiitoshiki.com\/improvesociety\/wp-content\/uploads\/Fig3.png\"><img loading=\"lazy\" decoding=\"async\" src=\"\/\/fujiitoshiki.com\/improvesociety\/wp-content\/uploads\/Fig3-300x300.png\" alt=\"Fig3. probability and logarithm of logit\" width=\"300\" height=\"300\" class=\"size-medium wp-image-2030\" srcset=\"https:\/\/www.fujiitoshiki.com\/improvesociety\/wp-content\/uploads\/Fig3-300x300.png 300w, https:\/\/www.fujiitoshiki.com\/improvesociety\/wp-content\/uploads\/Fig3-150x150.png 150w, https:\/\/www.fujiitoshiki.com\/improvesociety\/wp-content\/uploads\/Fig3.png 303w\" sizes=\"auto, (max-width: 300px) 85vw, 300px\" \/><\/a><figcaption id=\"caption-attachment-2030\" class=\"wp-caption-text\">Fig3. probability and logit<\/figcaption><\/figure>\n<\/div>","protected":false},"excerpt":{"rendered":"<p>In logistic regression analysis, probability is converted to odds, p\/(1-p), and odds is converted to logarithm &hellip; <a href=\"https:\/\/www.fujiitoshiki.com\/improvesociety\/?p=2035\" class=\"more-link\"><span class=\"screen-reader-text\">&#8220;Why probability should be converted to logarithm of odds (logit) in logistic regression analysis?&#8221; \u306e<\/span>\u7d9a\u304d\u3092\u8aad\u3080<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_crdt_document":"","_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"categories":[7],"tags":[333,331,33,328,329,332,330,327],"class_list":["post-2035","post","type-post","status-publish","format-standard","hentry","category-statistics","tag-all-real-number","tag-binomial-distribution","tag-logarithm","tag-logistic-regression-analysis","tag-logit","tag-multiple-regression-analysis","tag-odds","tag-probability"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/www.fujiitoshiki.com\/improvesociety\/index.php?rest_route=\/wp\/v2\/posts\/2035","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.fujiitoshiki.com\/improvesociety\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.fujiitoshiki.com\/improvesociety\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.fujiitoshiki.com\/improvesociety\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.fujiitoshiki.com\/improvesociety\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=2035"}],"version-history":[{"count":7,"href":"https:\/\/www.fujiitoshiki.com\/improvesociety\/index.php?rest_route=\/wp\/v2\/posts\/2035\/revisions"}],"predecessor-version":[{"id":6023,"href":"https:\/\/www.fujiitoshiki.com\/improvesociety\/index.php?rest_route=\/wp\/v2\/posts\/2035\/revisions\/6023"}],"wp:attachment":[{"href":"https:\/\/www.fujiitoshiki.com\/improvesociety\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2035"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.fujiitoshiki.com\/improvesociety\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=2035"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.fujiitoshiki.com\/improvesociety\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=2035"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}