{"id":4554,"date":"2026-08-11T10:25:23","date_gmt":"2026-08-11T08:25:23","guid":{"rendered":"https:\/\/ellistat.com\/?post_type=guide-dutilisateur&#038;p=4554"},"modified":"2026-08-11T10:25:23","modified_gmt":"2026-08-11T08:25:23","slug":"population-models","status":"publish","type":"guide-dutilisateur","link":"https:\/\/ellistat.com\/en\/guide-dutilisateur\/les-representations-de-population\/","title":{"rendered":"Population Models"},"content":{"rendered":"<ul class=\"wp-block-list\">\n<li><strong>Histogram<\/strong>\u00a0: the shape of the distribution. Skewness, dispersion, bimodality: a double peak almost always indicates a mixture of two populations.\u00a0<\/li>\n<\/ul>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"964\" height=\"786\" src=\"https:\/\/ellistat.com\/wp-content\/uploads\/histogramme.png\" alt=\"\" class=\"wp-image-4555\" srcset=\"https:\/\/ellistat.com\/wp-content\/uploads\/histogramme.png 964w, https:\/\/ellistat.com\/wp-content\/uploads\/histogramme-300x245.png 300w, https:\/\/ellistat.com\/wp-content\/uploads\/histogramme-768x626.png 768w, https:\/\/ellistat.com\/wp-content\/uploads\/histogramme-15x12.png 15w\" sizes=\"auto, (max-width: 964px) 100vw, 964px\" \/><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">You can choose whether to have an independent X-axis for each histogram, the same X-axis for all histograms, or all histograms stacked.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Moustache Box<\/strong>\u00a0: the median, the quartiles, the range. This is a representation of the\u00a0<strong>comparison<\/strong>\u00a0: Several boxes side by side can be read at a glance, whereas multiple histograms get in the way.<\/li>\n\n\n\n<li><strong>Line<\/strong>\u00a0: the values in the order in which they were collected. The chronology that the histogram ignores.<\/li>\n\n\n\n<li><strong>Control Chart<\/strong>\u00a0: the line, with its control limits and detection rules.<\/li>\n\n\n\n<li><strong>Ogive Diagram<\/strong>\u00a0: the cumulative distribution. This directly answers the question, \u00abWhat proportion is below a given value?\u00bb.<\/li>\n<\/ul>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"964\" height=\"570\" src=\"https:\/\/ellistat.com\/wp-content\/uploads\/histogramme2.png\" alt=\"\" class=\"wp-image-4556\" srcset=\"https:\/\/ellistat.com\/wp-content\/uploads\/histogramme2.png 964w, https:\/\/ellistat.com\/wp-content\/uploads\/histogramme2-300x177.png 300w, https:\/\/ellistat.com\/wp-content\/uploads\/histogramme2-768x454.png 768w, https:\/\/ellistat.com\/wp-content\/uploads\/histogramme2-18x12.png 18w\" sizes=\"auto, (max-width: 964px) 100vw, 964px\" \/><\/figure>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Better Than Current<\/strong>\u00a0: performs a nonparametric comparison of two or more modalities<\/li>\n\n\n\n<li><strong>ROC Curve<\/strong>\u00a0: evaluates the ability of a quantitative measure to distinguish between two categories and provides the optimal threshold.<\/li>\n<\/ul>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p class=\"wp-block-paragraph\">\ud83d\udca1\u00a0<strong>A histogram and a box-and-whisker plot do not answer the same question.<\/strong>\u00a0A histogram provides a detailed description of a population; a box plot compares multiple populations. When examining two groups, start with the box plots, then open the histogram for the group in question.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u26a0\ufe0f\u00a0<strong>Paired data.<\/strong>\u00a0If your two sets of data are two measurements of the same parts\u2014before and after treatment\u2014or two instruments used on the same samples, you must indicate this in the \u00abComparison Type\u00bb field. The paired test is much more powerful because it eliminates variability between samples. Treating paired data as independent often leads to the conclusion that \u00abthere is no difference\u00bb when in fact there is a clear difference.<\/p>\n<\/blockquote>\n\n\n\n<h2 class=\"wp-block-heading\">The ROC Curve in Practice<\/h2>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"964\" height=\"654\" src=\"https:\/\/ellistat.com\/wp-content\/uploads\/courbeROC.png\" alt=\"\" class=\"wp-image-4557\" srcset=\"https:\/\/ellistat.com\/wp-content\/uploads\/courbeROC.png 964w, https:\/\/ellistat.com\/wp-content\/uploads\/courbeROC-300x204.png 300w, https:\/\/ellistat.com\/wp-content\/uploads\/courbeROC-768x521.png 768w, https:\/\/ellistat.com\/wp-content\/uploads\/courbeROC-18x12.png 18w\" sizes=\"auto, (max-width: 964px) 100vw, 964px\" \/><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">She answers: Does this measure help us make a decision?<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"> For example, can a vibration reading be used to distinguish between bearings that will fail and those that will hold up?<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>The further the curve deviates from the diagonal toward the upper-left corner, the better the separation; ;<\/li>\n\n\n\n<li>The\u2019<strong>area under the curve (AUC)<\/strong>\u00a0summarizes this power with a single number: 0.5 means \u00abno better than chance,\u00bb and 1 means a perfect separation; ;<\/li>\n\n\n\n<li>The proposed threshold balances the two types of errors: missing a defect and rejecting a good part.<\/li>\n<\/ul>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p class=\"wp-block-paragraph\">\ud83d\udca1 The right threshold depends on the&nbsp;<strong>cost<\/strong>&nbsp;between the two errors, which is rarely symmetrical. The statistically optimal threshold is not always the economically optimal threshold: it\u2019s up to you to adjust it with full knowledge of the facts.<\/p>\n<\/blockquote>","protected":false},"featured_media":0,"menu_order":60,"template":"","meta":{"_acf_changed":true},"menu-guide-dutilisateur":[21],"class_list":["post-4554","guide-dutilisateur","type-guide-dutilisateur","status-publish","hentry","menu-guide-dutilisateur-3-graphiques"],"acf":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v28.2 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>Les repr\u00e9sentations de population - Ellistat<\/title>\n<meta name=\"description\" content=\"Histogramme, bo\u00eete \u00e0 moustache, carte de contr\u00f4le, courbe ROC : quelle repr\u00e9sentation choisir pour analyser une distribution de donn\u00e9es ?\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/ellistat.com\/en\/users-guide\/population-models\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Les repr\u00e9sentations de population - Ellistat\" \/>\n<meta property=\"og:description\" content=\"Histogramme, bo\u00eete \u00e0 moustache, carte de contr\u00f4le, courbe ROC : quelle repr\u00e9sentation choisir pour analyser une distribution de donn\u00e9es ?\" \/>\n<meta property=\"og:url\" content=\"https:\/\/ellistat.com\/en\/users-guide\/population-models\/\" \/>\n<meta property=\"og:site_name\" content=\"Ellistat\" \/>\n<meta property=\"og:image\" content=\"https:\/\/ellistat.com\/wp-content\/uploads\/histogramme.png\" \/>\n\t<meta property=\"og:image:width\" content=\"964\" \/>\n\t<meta property=\"og:image:height\" content=\"786\" \/>\n\t<meta property=\"og:image:type\" content=\"image\/png\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data1\" content=\"2 minutes\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\\\/\\\/schema.org\",\"@graph\":[{\"@type\":\"WebPage\",\"@id\":\"https:\\\/\\\/ellistat.com\\\/guide-dutilisateur\\\/les-representations-de-population\\\/\",\"url\":\"https:\\\/\\\/ellistat.com\\\/guide-dutilisateur\\\/les-representations-de-population\\\/\",\"name\":\"Les repr\u00e9sentations de population - Ellistat\",\"isPartOf\":{\"@id\":\"https:\\\/\\\/ellistat.com\\\/#website\"},\"primaryImageOfPage\":{\"@id\":\"https:\\\/\\\/ellistat.com\\\/guide-dutilisateur\\\/les-representations-de-population\\\/#primaryimage\"},\"image\":{\"@id\":\"https:\\\/\\\/ellistat.com\\\/guide-dutilisateur\\\/les-representations-de-population\\\/#primaryimage\"},\"thumbnailUrl\":\"https:\\\/\\\/ellistat.com\\\/wp-content\\\/uploads\\\/histogramme.png\",\"datePublished\":\"2026-08-11T08:25:23+00:00\",\"description\":\"Histogramme, bo\u00eete \u00e0 moustache, carte de contr\u00f4le, courbe ROC : quelle repr\u00e9sentation choisir pour analyser une distribution de donn\u00e9es ?\",\"breadcrumb\":{\"@id\":\"https:\\\/\\\/ellistat.com\\\/guide-dutilisateur\\\/les-representations-de-population\\\/#breadcrumb\"},\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\\\/\\\/ellistat.com\\\/guide-dutilisateur\\\/les-representations-de-population\\\/\"]}]},{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\\\/\\\/ellistat.com\\\/guide-dutilisateur\\\/les-representations-de-population\\\/#primaryimage\",\"url\":\"https:\\\/\\\/ellistat.com\\\/wp-content\\\/uploads\\\/histogramme.png\",\"contentUrl\":\"https:\\\/\\\/ellistat.com\\\/wp-content\\\/uploads\\\/histogramme.png\"},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\\\/\\\/ellistat.com\\\/guide-dutilisateur\\\/les-representations-de-population\\\/#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Accueil\",\"item\":\"https:\\\/\\\/ellistat.com\\\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"Les repr\u00e9sentations de population\"}]},{\"@type\":\"WebSite\",\"@id\":\"https:\\\/\\\/ellistat.com\\\/#website\",\"url\":\"https:\\\/\\\/ellistat.com\\\/\",\"name\":\"Ellistat\",\"description\":\"La suite qualit\u00e9 de l&#039;industrie m\u00e9canique\",\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":{\"@type\":\"EntryPoint\",\"urlTemplate\":\"https:\\\/\\\/ellistat.com\\\/?s={search_term_string}\"},\"query-input\":{\"@type\":\"PropertyValueSpecification\",\"valueRequired\":true,\"valueName\":\"search_term_string\"}}],\"inLanguage\":\"en-US\"}]}<\/script>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"Population Estimates - Ellistat","description":"Histogram, box-and-whisker plot, control chart, ROC curve: Which graphical representation should you choose to analyze a data distribution?","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:\/\/ellistat.com\/en\/users-guide\/population-models\/","og_locale":"en_US","og_type":"article","og_title":"Les repr\u00e9sentations de population - Ellistat","og_description":"Histogramme, bo\u00eete \u00e0 moustache, carte de contr\u00f4le, courbe ROC : quelle repr\u00e9sentation choisir pour analyser une distribution de donn\u00e9es ?","og_url":"https:\/\/ellistat.com\/en\/users-guide\/population-models\/","og_site_name":"Ellistat","og_image":[{"width":964,"height":786,"url":"https:\/\/ellistat.com\/wp-content\/uploads\/histogramme.png","type":"image\/png"}],"twitter_card":"summary_large_image","twitter_misc":{"Est. reading time":"2 minutes"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"WebPage","@id":"https:\/\/ellistat.com\/guide-dutilisateur\/les-representations-de-population\/","url":"https:\/\/ellistat.com\/guide-dutilisateur\/les-representations-de-population\/","name":"Population Estimates - Ellistat","isPartOf":{"@id":"https:\/\/ellistat.com\/#website"},"primaryImageOfPage":{"@id":"https:\/\/ellistat.com\/guide-dutilisateur\/les-representations-de-population\/#primaryimage"},"image":{"@id":"https:\/\/ellistat.com\/guide-dutilisateur\/les-representations-de-population\/#primaryimage"},"thumbnailUrl":"https:\/\/ellistat.com\/wp-content\/uploads\/histogramme.png","datePublished":"2026-08-11T08:25:23+00:00","description":"Histogram, box-and-whisker plot, control chart, ROC curve: Which graphical representation should you choose to analyze a data distribution?","breadcrumb":{"@id":"https:\/\/ellistat.com\/guide-dutilisateur\/les-representations-de-population\/#breadcrumb"},"inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":["https:\/\/ellistat.com\/guide-dutilisateur\/les-representations-de-population\/"]}]},{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/ellistat.com\/guide-dutilisateur\/les-representations-de-population\/#primaryimage","url":"https:\/\/ellistat.com\/wp-content\/uploads\/histogramme.png","contentUrl":"https:\/\/ellistat.com\/wp-content\/uploads\/histogramme.png"},{"@type":"BreadcrumbList","@id":"https:\/\/ellistat.com\/guide-dutilisateur\/les-representations-de-population\/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Accueil","item":"https:\/\/ellistat.com\/"},{"@type":"ListItem","position":2,"name":"Les repr\u00e9sentations de population"}]},{"@type":"WebSite","@id":"https:\/\/ellistat.com\/#website","url":"https:\/\/ellistat.com\/","name":"Ellistat","description":"The quality suite for the mechanical engineering industry","potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/ellistat.com\/?s={search_term_string}"},"query-input":{"@type":"PropertyValueSpecification","valueRequired":true,"valueName":"search_term_string"}}],"inLanguage":"en-US"}]}},"_links":{"self":[{"href":"https:\/\/ellistat.com\/en\/wp-json\/wp\/v2\/guide-dutilisateur\/4554","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ellistat.com\/en\/wp-json\/wp\/v2\/guide-dutilisateur"}],"about":[{"href":"https:\/\/ellistat.com\/en\/wp-json\/wp\/v2\/types\/guide-dutilisateur"}],"wp:attachment":[{"href":"https:\/\/ellistat.com\/en\/wp-json\/wp\/v2\/media?parent=4554"}],"wp:term":[{"taxonomy":"menu-guide-dutilisateur","embeddable":true,"href":"https:\/\/ellistat.com\/en\/wp-json\/wp\/v2\/menu-guide-dutilisateur?post=4554"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}