{"id":676,"date":"2011-11-14T11:23:09","date_gmt":"2011-11-14T10:23:09","guid":{"rendered":"https:\/\/abcdr.guyader.pro\/?p=676"},"modified":"2018-04-07T23:59:29","modified_gmt":"2018-04-07T22:59:29","slug":"comment-faire-un-test-de-normalite-avec-r-le-test-de-shapiro-wilk","status":"publish","type":"post","link":"https:\/\/thinkr.fr\/abcdr\/comment-faire-un-test-de-normalite-avec-r-le-test-de-shapiro-wilk\/","title":{"rendered":"Comment faire un test de normalit\u00e9 avec R ? : Le test de Shapiro-Wilk"},"content":{"rendered":"<p>Le test de Shapiro-Wilk teste l&rsquo;hypoth\u00e8se nulle selon laquelle l&rsquo;\u00e9chantillon est issu d&rsquo;une population normalement distribu\u00e9e. <br \/>Si la p-value est inf\u00e9rieure au niveau alpha fix\u00e9 (souvent 0.05) alors on rejette l&rsquo;hypoth\u00e8se nulle et on en conclut que l&rsquo;\u00e9chantillon est issu d&rsquo;une population qui n&rsquo;est pas normalement distribu\u00e9e.<\/p>\n<p>Voici un exemple avec R :<\/p>\n<pre><code><br \/><br \/>#on simule des \u00e9chantillons<br \/><br \/>#d issu d'une loi normale<br \/>d&lt;-rnorm(100, mean = 5, sd = 3)<br \/><br \/>#e issu d'une loi uniforme<br \/>e&lt;-runif(100, min = 2, max = 4)<br \/><br \/># on r\u00e9alise un test de shapiro<br \/><br \/>shapiro.test(d)<br \/>qqnorm(d) #p=0.35 on ne rejette pas l'hypoth\u00e8se et on v\u00e9rifie avec un QQplot<br \/><br \/>shapiro.test(e)<br \/>qqnorm(e) # p=0.00036 on rejette l'hypoth\u00e8se et on v\u00e9rifie avec un QQplot<br \/><br \/><\/code><\/pre>\n<p>Ce test n&rsquo;est qu&rsquo;un test parmi les autres, n&rsquo;h\u00e9sitez pas \u00e0 en utiliser d&rsquo;autres avant de tirer des conclusions (par exemple faire des QQplot).<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Le test de Shapiro-Wilk teste l&rsquo;hypoth\u00e8se nulle selon laquelle l&rsquo;\u00e9chantillon est issu d&rsquo;une population normalement distribu\u00e9e. Si la p-value est inf\u00e9rieure au niveau alpha fix\u00e9 (souvent 0.05) alors on rejette l&rsquo;hypoth\u00e8se nulle et on en conclut que l&rsquo;\u00e9chantillon est issu d&rsquo;une population qui n&rsquo;est pas normalement distribu\u00e9e. Voici un exemple avec R : #on simule des \u00e9chantillons#d issu d&rsquo;une loi normaled&lt;-rnorm(100, mean = 5, sd = 3)#e issu d&rsquo;une loi uniformee&lt;-runif(100, min = 2, max = 4)# on r\u00e9alise un test de shapiroshapiro.test(d)qqnorm(d) #p=0.35 on ne rejette pas l&rsquo;hypoth\u00e8se et on v\u00e9rifie avec un QQplotshapiro.test(e)qqnorm(e) # p=0.00036 on rejette l&rsquo;hypoth\u00e8se et on v\u00e9rifie avec un<a class=\"more-link\" href=\"https:\/\/thinkr.fr\/abcdr\/comment-faire-un-test-de-normalite-avec-r-le-test-de-shapiro-wilk\/\">Read More &rarr;<\/a><\/p>\n","protected":false},"author":6,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"content-type":"","rop_custom_images_group":[],"rop_custom_messages_group":[],"rop_publish_now":"initial","rop_publish_now_accounts":{"twitter_399453572_399453572":""},"rop_publish_now_history":[],"rop_publish_now_status":"pending","jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[4,21],"tags":[],"class_list":{"0":"entry","1":"post","2":"publish","3":"author-melen","4":"post-676","6":"format-standard","7":"category-base-indispensable","8":"category-test"},"acf":[],"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/p9O7Sx-aU","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/thinkr.fr\/abcdr\/wp-json\/wp\/v2\/posts\/676","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/thinkr.fr\/abcdr\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/thinkr.fr\/abcdr\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/thinkr.fr\/abcdr\/wp-json\/wp\/v2\/users\/6"}],"replies":[{"embeddable":true,"href":"https:\/\/thinkr.fr\/abcdr\/wp-json\/wp\/v2\/comments?post=676"}],"version-history":[{"count":2,"href":"https:\/\/thinkr.fr\/abcdr\/wp-json\/wp\/v2\/posts\/676\/revisions"}],"predecessor-version":[{"id":4120,"href":"https:\/\/thinkr.fr\/abcdr\/wp-json\/wp\/v2\/posts\/676\/revisions\/4120"}],"wp:attachment":[{"href":"https:\/\/thinkr.fr\/abcdr\/wp-json\/wp\/v2\/media?parent=676"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/thinkr.fr\/abcdr\/wp-json\/wp\/v2\/categories?post=676"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/thinkr.fr\/abcdr\/wp-json\/wp\/v2\/tags?post=676"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}