{"id":278,"date":"2018-07-28T17:56:11","date_gmt":"2018-07-28T15:56:11","guid":{"rendered":"https:\/\/blogs.futura-sciences.com\/lehning\/?p=278"},"modified":"2018-08-19T10:08:55","modified_gmt":"2018-08-19T08:08:55","slug":"denombrer-linvisible","status":"publish","type":"post","link":"https:\/\/blogs.futura-sciences.com\/lehning\/2018\/07\/28\/denombrer-linvisible\/","title":{"rendered":"D\u00e9nombrer l’invisible"},"content":{"rendered":"

Certains chiffres entendus sur les m\u00e9dias sont surprenants, surtout quand ils sont donn\u00e9s sans explication.<\/span><\/span><\/p>\n

D\u00e9nombrer les migrants<\/h2>\n

Aujourd\u2019hui, vous apprenez que, selon le minist\u00e8re de l\u2019int\u00e9rieur, il y aurait entre 200000 et 400000 clandestins pr\u00e9sents sur le territoire fran\u00e7ais. D\u2019o\u00f9 viennent ces chiffres\u00a0? Le propre des clandestins \u2026 est de l\u2019\u00eatre, et donc d\u2019\u00e9chapper \u00e0 tout recensement. <\/span><\/span><\/p>\n

\"\"
Comment d\u00e9nombrer ceux qui se cachent ?<\/figcaption><\/figure>\n

La d\u00e9mographie permet cependant d\u2019\u00e9valuer leur nombre. Pour commencer, nous connaissons les taux de mortalit\u00e9 par \u00e2ge et par origine. Nous pouvons estimer que les taux sont environ les m\u00eames pour les clandestins. Du nombre de d\u00e9c\u00e9d\u00e9s sans papiers, nous pouvons donc d\u00e9duire une approximation du nombre de vivants sans papiers. La m\u00eame op\u00e9ration est possible gr\u00e2ce aux naissances. Les recensements permettent aussi de se douter de la pr\u00e9sence de clandestins, quand les nombres recens\u00e9s ne correspondent pas aux nombres pr\u00e9vus.<\/span><\/span><\/p>\n

D\u00e9nombrer les s\u00e9ropositifs<\/h2>\n

De m\u00eame, vous apprenez que 150000 personnes sont porteuses du virus du sida (c\u2019est-\u00e0-dire s\u00e9ropositives) en France, dont 40000 l\u2019ignorent. Comment peut-on faire une telle estimation\u00a0? S’ils l’ignorent, comment le savons-nous ? Ici encore, l\u2019id\u00e9e est de faire des recoupements. Sans rentrer dans toute la subtilit\u00e9 des d\u00e9tails, voyons le principe du calcul. Imaginons que nous connaissions le nombre de cas de sida diagnostiqu\u00e9s une certaine ann\u00e9e, 500 par exemple. Parmi ceux-ci, 370 correspondent \u00e0 des personnes dont la s\u00e9ropositivit\u00e9 \u00e9tait connue. Ainsi 130 \u00e9taient des s\u00e9ropositifs inconnus les ann\u00e9es pr\u00e9c\u00e9dentes. Il est donc l\u00e9gitime d\u2019estimer que pour 370 s\u00e9ropositifs connus, il en existe 130 inconnus. Nous multiplions le nombre de s\u00e9ropositifs connus (110000 par exemple) par le rapport 130\u00a0\/\u00a0370 pour en d\u00e9duire le nombre de s\u00e9ropositifs inconnus, ce qui donne un peu moins de 40\u00a0000. Bien s\u00fbr, le mod\u00e8le est un peu plus raffin\u00e9 que cela car certains milieux sont plus conscients du danger de cette maladie que d\u2019autres et pratiquent les tests plus volontiers. Les taux entre connus et inconnus diff\u00e8rent alors selon le milieu. Dans tous les cas, \u00e0 d\u00e9faut d\u2019un vaccin, l\u2019id\u00e9al pour enrayer l\u2019\u00e9pid\u00e9mie et mieux soigner les malades serait un test annuel pour tous. Ce serait malgr\u00e9 tout co\u00fbteux et difficile \u00e0 mettre en place.<\/span><\/span><\/p>\n","protected":false},"excerpt":{"rendered":"

Certains chiffres entendus sur les m\u00e9dias sont surprenants, surtout quand ils sont donn\u00e9s sans explication. D\u00e9nombrer les migrants Aujourd\u2019hui, vous apprenez que, selon le minist\u00e8re de l\u2019int\u00e9rieur, il y aurait entre 200000 et 400000 clandestins pr\u00e9sents sur le territoire fran\u00e7ais. D\u2019o\u00f9 viennent ces chiffres\u00a0? Le propre des clandestins \u2026 est de l\u2019\u00eatre, et donc d\u2019\u00e9chapper … Continuer la lecture de D\u00e9nombrer l’invisible<\/span> →<\/span><\/a><\/p>\n","protected":false},"author":12,"featured_media":280,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":"","_links_to":"","_links_to_target":""},"categories":[29,15],"tags":[132,133,135,134,129],"class_list":["post-278","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-maths-2","category-reflexions","tag-denombrement","tag-migrants","tag-seropositivite","tag-sida","tag-statistiques"],"yoast_head":"\nD\u00e9nombrer l'invisible, par Herv\u00e9 Lehning<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/blogs.futura-sciences.com\/lehning\/2018\/07\/28\/denombrer-linvisible\/\" \/>\n<meta property=\"og:locale\" content=\"fr_FR\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"D\u00e9nombrer l'invisible, par Herv\u00e9 Lehning\" \/>\n<meta property=\"og:description\" content=\"Certains chiffres entendus sur les m\u00e9dias sont surprenants, surtout quand ils sont donn\u00e9s sans explication. D\u00e9nombrer les migrants Aujourd\u2019hui, vous apprenez que, selon le minist\u00e8re de l\u2019int\u00e9rieur, il y aurait entre 200000 et 400000 clandestins pr\u00e9sents sur le territoire fran\u00e7ais. D\u2019o\u00f9 viennent ces chiffres\u00a0? Le propre des clandestins \u2026 est de l\u2019\u00eatre, et donc d\u2019\u00e9chapper … Continuer la lecture de D\u00e9nombrer l’invisible →\" \/>\n<meta property=\"og:url\" content=\"https:\/\/blogs.futura-sciences.com\/lehning\/2018\/07\/28\/denombrer-linvisible\/\" \/>\n<meta property=\"og:site_name\" content=\"MATH'MONDE, le blog d'Herv\u00e9 LEHNING, agr\u00e9g\u00e9 de math\u00e9matiques\" \/>\n<meta property=\"article:published_time\" content=\"2018-07-28T15:56:11+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2018-08-19T08:08:55+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/blogs.futura-sciences.com\/lehning\/wp-content\/uploads\/sites\/13\/2018\/06\/Foule-invisible.jpg\" \/>\n\t<meta property=\"og:image:width\" content=\"850\" \/>\n\t<meta property=\"og:image:height\" content=\"567\" \/>\n\t<meta property=\"og:image:type\" content=\"image\/jpeg\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"\u00c9crit par\" \/>\n\t<meta name=\"twitter:data1\" content=\"\" \/>\n\t<meta name=\"twitter:label2\" content=\"Dur\u00e9e de lecture estim\u00e9e\" \/>\n\t<meta name=\"twitter:data2\" content=\"2 minutes\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"WebPage\",\"@id\":\"https:\/\/blogs.futura-sciences.com\/lehning\/2018\/07\/28\/denombrer-linvisible\/\",\"url\":\"https:\/\/blogs.futura-sciences.com\/lehning\/2018\/07\/28\/denombrer-linvisible\/\",\"name\":\"D\u00e9nombrer l'invisible, par Herv\u00e9 Lehning\",\"isPartOf\":{\"@id\":\"https:\/\/blogs.futura-sciences.com\/lehning\/#website\"},\"primaryImageOfPage\":{\"@id\":\"https:\/\/blogs.futura-sciences.com\/lehning\/2018\/07\/28\/denombrer-linvisible\/#primaryimage\"},\"image\":{\"@id\":\"https:\/\/blogs.futura-sciences.com\/lehning\/2018\/07\/28\/denombrer-linvisible\/#primaryimage\"},\"thumbnailUrl\":\"https:\/\/blogs.futura-sciences.com\/lehning\/wp-content\/uploads\/sites\/13\/2018\/06\/Foule-invisible.jpg\",\"datePublished\":\"2018-07-28T15:56:11+00:00\",\"dateModified\":\"2018-08-19T08:08:55+00:00\",\"author\":{\"@id\":\"\"},\"breadcrumb\":{\"@id\":\"https:\/\/blogs.futura-sciences.com\/lehning\/2018\/07\/28\/denombrer-linvisible\/#breadcrumb\"},\"inLanguage\":\"fr-FR\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\/\/blogs.futura-sciences.com\/lehning\/2018\/07\/28\/denombrer-linvisible\/\"]}]},{\"@type\":\"ImageObject\",\"inLanguage\":\"fr-FR\",\"@id\":\"https:\/\/blogs.futura-sciences.com\/lehning\/2018\/07\/28\/denombrer-linvisible\/#primaryimage\",\"url\":\"https:\/\/blogs.futura-sciences.com\/lehning\/wp-content\/uploads\/sites\/13\/2018\/06\/Foule-invisible.jpg\",\"contentUrl\":\"https:\/\/blogs.futura-sciences.com\/lehning\/wp-content\/uploads\/sites\/13\/2018\/06\/Foule-invisible.jpg\",\"width\":850,\"height\":567},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\/\/blogs.futura-sciences.com\/lehning\/2018\/07\/28\/denombrer-linvisible\/#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Accueil\",\"item\":\"https:\/\/blogs.futura-sciences.com\/lehning\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"D\u00e9nombrer l’invisible\"}]},{\"@type\":\"WebSite\",\"@id\":\"https:\/\/blogs.futura-sciences.com\/lehning\/#website\",\"url\":\"https:\/\/blogs.futura-sciences.com\/lehning\/\",\"name\":\"MATH'MONDE, le blog d'Herv\u00e9 LEHNING, agr\u00e9g\u00e9 de math\u00e9matiques\",\"description\":\"Comment comprendre le monde moderne sans culture math\u00e9matique ? Acc\u00e9der \u00e0 celle-ci n\u2019exige cependant pas d\u2019apprendre \u00e0 r\u00e9soudre la moindre \u00e9quation.\",\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":{\"@type\":\"EntryPoint\",\"urlTemplate\":\"https:\/\/blogs.futura-sciences.com\/lehning\/?s={search_term_string}\"},\"query-input\":{\"@type\":\"PropertyValueSpecification\",\"valueRequired\":true,\"valueName\":\"search_term_string\"}}],\"inLanguage\":\"fr-FR\"},{\"@type\":\"Person\",\"@id\":\"\",\"url\":\"https:\/\/blogs.futura-sciences.com\/lehning\/author\/\"}]}<\/script>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"D\u00e9nombrer l'invisible, par Herv\u00e9 Lehning","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/blogs.futura-sciences.com\/lehning\/2018\/07\/28\/denombrer-linvisible\/","og_locale":"fr_FR","og_type":"article","og_title":"D\u00e9nombrer l'invisible, par Herv\u00e9 Lehning","og_description":"Certains chiffres entendus sur les m\u00e9dias sont surprenants, surtout quand ils sont donn\u00e9s sans explication. D\u00e9nombrer les migrants Aujourd\u2019hui, vous apprenez que, selon le minist\u00e8re de l\u2019int\u00e9rieur, il y aurait entre 200000 et 400000 clandestins pr\u00e9sents sur le territoire fran\u00e7ais. D\u2019o\u00f9 viennent ces chiffres\u00a0? Le propre des clandestins \u2026 est de l\u2019\u00eatre, et donc d\u2019\u00e9chapper … Continuer la lecture de D\u00e9nombrer l’invisible →","og_url":"https:\/\/blogs.futura-sciences.com\/lehning\/2018\/07\/28\/denombrer-linvisible\/","og_site_name":"MATH'MONDE, le blog d'Herv\u00e9 LEHNING, agr\u00e9g\u00e9 de math\u00e9matiques","article_published_time":"2018-07-28T15:56:11+00:00","article_modified_time":"2018-08-19T08:08:55+00:00","og_image":[{"width":850,"height":567,"url":"https:\/\/blogs.futura-sciences.com\/lehning\/wp-content\/uploads\/sites\/13\/2018\/06\/Foule-invisible.jpg","type":"image\/jpeg"}],"twitter_card":"summary_large_image","twitter_misc":{"\u00c9crit par":"","Dur\u00e9e de lecture estim\u00e9e":"2 minutes"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"WebPage","@id":"https:\/\/blogs.futura-sciences.com\/lehning\/2018\/07\/28\/denombrer-linvisible\/","url":"https:\/\/blogs.futura-sciences.com\/lehning\/2018\/07\/28\/denombrer-linvisible\/","name":"D\u00e9nombrer l'invisible, par Herv\u00e9 Lehning","isPartOf":{"@id":"https:\/\/blogs.futura-sciences.com\/lehning\/#website"},"primaryImageOfPage":{"@id":"https:\/\/blogs.futura-sciences.com\/lehning\/2018\/07\/28\/denombrer-linvisible\/#primaryimage"},"image":{"@id":"https:\/\/blogs.futura-sciences.com\/lehning\/2018\/07\/28\/denombrer-linvisible\/#primaryimage"},"thumbnailUrl":"https:\/\/blogs.futura-sciences.com\/lehning\/wp-content\/uploads\/sites\/13\/2018\/06\/Foule-invisible.jpg","datePublished":"2018-07-28T15:56:11+00:00","dateModified":"2018-08-19T08:08:55+00:00","author":{"@id":""},"breadcrumb":{"@id":"https:\/\/blogs.futura-sciences.com\/lehning\/2018\/07\/28\/denombrer-linvisible\/#breadcrumb"},"inLanguage":"fr-FR","potentialAction":[{"@type":"ReadAction","target":["https:\/\/blogs.futura-sciences.com\/lehning\/2018\/07\/28\/denombrer-linvisible\/"]}]},{"@type":"ImageObject","inLanguage":"fr-FR","@id":"https:\/\/blogs.futura-sciences.com\/lehning\/2018\/07\/28\/denombrer-linvisible\/#primaryimage","url":"https:\/\/blogs.futura-sciences.com\/lehning\/wp-content\/uploads\/sites\/13\/2018\/06\/Foule-invisible.jpg","contentUrl":"https:\/\/blogs.futura-sciences.com\/lehning\/wp-content\/uploads\/sites\/13\/2018\/06\/Foule-invisible.jpg","width":850,"height":567},{"@type":"BreadcrumbList","@id":"https:\/\/blogs.futura-sciences.com\/lehning\/2018\/07\/28\/denombrer-linvisible\/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Accueil","item":"https:\/\/blogs.futura-sciences.com\/lehning\/"},{"@type":"ListItem","position":2,"name":"D\u00e9nombrer l’invisible"}]},{"@type":"WebSite","@id":"https:\/\/blogs.futura-sciences.com\/lehning\/#website","url":"https:\/\/blogs.futura-sciences.com\/lehning\/","name":"MATH'MONDE, le blog d'Herv\u00e9 LEHNING, agr\u00e9g\u00e9 de math\u00e9matiques","description":"Comment comprendre le monde moderne sans culture math\u00e9matique ? Acc\u00e9der \u00e0 celle-ci n\u2019exige cependant pas d\u2019apprendre \u00e0 r\u00e9soudre la moindre \u00e9quation.","potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/blogs.futura-sciences.com\/lehning\/?s={search_term_string}"},"query-input":{"@type":"PropertyValueSpecification","valueRequired":true,"valueName":"search_term_string"}}],"inLanguage":"fr-FR"},{"@type":"Person","@id":"","url":"https:\/\/blogs.futura-sciences.com\/lehning\/author\/"}]}},"_links":{"self":[{"href":"https:\/\/blogs.futura-sciences.com\/lehning\/wp-json\/wp\/v2\/posts\/278","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blogs.futura-sciences.com\/lehning\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blogs.futura-sciences.com\/lehning\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.futura-sciences.com\/lehning\/wp-json\/wp\/v2\/users\/12"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.futura-sciences.com\/lehning\/wp-json\/wp\/v2\/comments?post=278"}],"version-history":[{"count":3,"href":"https:\/\/blogs.futura-sciences.com\/lehning\/wp-json\/wp\/v2\/posts\/278\/revisions"}],"predecessor-version":[{"id":283,"href":"https:\/\/blogs.futura-sciences.com\/lehning\/wp-json\/wp\/v2\/posts\/278\/revisions\/283"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/blogs.futura-sciences.com\/lehning\/wp-json\/wp\/v2\/media\/280"}],"wp:attachment":[{"href":"https:\/\/blogs.futura-sciences.com\/lehning\/wp-json\/wp\/v2\/media?parent=278"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.futura-sciences.com\/lehning\/wp-json\/wp\/v2\/categories?post=278"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.futura-sciences.com\/lehning\/wp-json\/wp\/v2\/tags?post=278"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}