{"id":1117,"date":"2023-07-27T14:52:53","date_gmt":"2023-07-27T14:52:53","guid":{"rendered":"https:\/\/statorials.org\/it\/normalizzare-i-dati-in-r\/"},"modified":"2023-07-27T14:52:53","modified_gmt":"2023-07-27T14:52:53","slug":"normalizzare-i-dati-in-r","status":"publish","type":"post","link":"https:\/\/statorials.org\/it\/normalizzare-i-dati-in-r\/","title":{"rendered":"Come standardizzare i dati in r: con esempi"},"content":{"rendered":"<p><\/p>\n<hr>\n<p><span style=\"color: #000000;\"><strong>Standardizzare<\/strong> un set di dati significa ridimensionare tutti i valori nel set di dati in modo tale che il valore medio sia 0 e la deviazione standard sia 1.<\/span><\/p>\n<p> <span style=\"color: #000000;\">Il modo pi\u00f9 comune per farlo \u00e8 utilizzare la standardizzazione del punteggio z, che scala i valori utilizzando la seguente formula:<\/span><\/p>\n<p> <span style=\"color: #000000;\"><strong>(x <sub>i<\/sub> \u2013 <span style=\"text-decoration: overline;\">x<\/span> ) \/ s<\/strong><\/span><\/p>\n<p> <span style=\"color: #000000;\">Oro:<\/span><\/p>\n<ul>\n<li> <span style=\"color: #000000;\"><strong>x <sub>i<\/sub><\/strong> : l&#8217;i <sup>-esimo<\/sup> valore del set di dati<\/span><\/li>\n<li> <span style=\"color: #000000;\"><strong><span style=\"text-decoration: overline;\">x<\/span><\/strong> : Il campione significa<\/span><\/li>\n<li> <span style=\"color: #000000;\"><strong>s<\/strong> : la deviazione standard del campione<\/span><\/li>\n<\/ul>\n<p> <span style=\"color: #000000;\">Gli esempi seguenti mostrano come utilizzare la funzione <a href=\"https:\/\/statorials.org\/it\/funzione-di-scala-in-r\/\" target=\"_blank\" rel=\"noopener\">scale()<\/a> con il pacchetto <strong>dplyr<\/strong> in R per ridimensionare una o pi\u00f9 variabili in un frame di dati utilizzando la standardizzazione z-score.<\/span><\/p>\n<h2> <span style=\"color: #000000;\"><strong>Standardizzare una singola variabile<\/strong><\/span><\/h2>\n<p> <span style=\"color: #000000;\">Il codice seguente mostra come ridimensionare una singola variabile in un frame di dati con tre variabili:<br \/><\/span><\/p>\n<pre style=\"background-color: #ececec; font-size: 15px;\"> <strong><span style=\"color: #993300;\">library<\/span> (dplyr)\n\n<span style=\"color: #008080;\">#make this example reproducible<\/span> \nset.seed(1)\n\n<span style=\"color: #008080;\">#create original data frame\n<\/span>df &lt;- data.frame(var1= runif(10, 0, 50), \n                 var2= runif(10, 2, 23),\n                 var3= runif(10, 5, 38))\n<span style=\"color: #008080;\">\n#view original data frame<\/span>\ndf\n\n        var1 var2 var3\n1 13.275433 6.325466 35.845273\n2 18.606195 5.707692 12.000703\n3 28.642668 16.427480 26.505234\n4 45.410389 10.066178 9.143318\n5 10.084097 18.166670 13.818282\n6 44.919484 12.451684 17.741765\n7 47.233763 17.069989 5.441881\n8 33.039890 22.830028 17.618803\n9 31.455702 9.980739 33.699798\n10 3.089314 18.326350 16.231517\n\n<span style=\"color: #008080;\">#scale <em>var1<\/em> to have mean = 0 and standard deviation = 1<\/span>\ndf2 &lt;- df %&gt;% <span style=\"color: #3366ff;\">mutate_at<\/span> (c(' <span style=\"color: #008000;\">var1<\/span> '), ~( <span style=\"color: #3366ff;\">scale<\/span> (.) %&gt;% <span style=\"color: #3366ff;\">as.vector<\/span> ))\ndf2\n\n          var1 var2 var3\n1 -0.90606801 6.325466 35.845273\n2 -0.56830963 5.707692 12.000703\n3 0.06760377 16.427480 26.505234\n4 1.13001072 10.066178 9.143318\n5 -1.10827188 18.166670 13.818282\n6 1.09890684 12.451684 17.741765\n7 1.24554014 17.069989 5.441881\n8 0.34621281 22.830028 17.618803\n9 0.24583830 9.980739 33.699798\n10 -1.55146305 18.326350 16.231517\n<\/strong><\/pre>\n<p> <span style=\"color: #000000;\">Si noti che solo la prima variabile \u00e8 stata ridimensionata mentre le altre due variabili sono rimaste le stesse. Possiamo rapidamente confermare che la nuova variabile scalata ha un valore medio pari a 0 e una deviazione standard pari a 1:<\/span><\/p>\n<pre style=\"background-color: #ececec; font-size: 15px;\"> <strong><span style=\"color: #008080;\">#calculate mean of scaled variable<\/span>\nmean(df2$var1)\n\n[1] -4.18502e-18 <span style=\"color: #008080;\">#basically zero<\/span>\n\n<span style=\"color: #008080;\">#calculate standard deviation of scaled variable<\/span> \nsd(df2$var1)\n\n[1] 1<\/strong><\/pre>\n<h2> <span style=\"color: #000000;\"><strong>Standardizzare pi\u00f9 variabili<\/strong><\/span><\/h2>\n<p> <span style=\"color: #000000;\">Il codice seguente mostra come ridimensionare pi\u00f9 variabili contemporaneamente in un frame di dati:<\/span><\/p>\n<pre style=\"background-color: #ececec; font-size: 15px;\"> <strong><span style=\"color: #993300;\">library<\/span> (dplyr)\n\n<span style=\"color: #008080;\">#make this example reproducible<\/span> \nset.seed(1)\n\n<span style=\"color: #008080;\">#create original data frame\n<\/span>df &lt;- data.frame(var1= runif(10, 0, 50), \n                 var2= runif(10, 2, 23),\n                 var3= runif(10, 5, 38))\n\n<span style=\"color: #008080;\">#scale <em>var1<\/em> and <em>var2<\/em> to have mean = 0 and standard deviation = 1<\/span>\ndf3 &lt;- df %&gt;% <span style=\"color: #3366ff;\">mutate_at<\/span> (c(' <span style=\"color: #008000;\">var1<\/span> ', ' <span style=\"color: #008000;\">var2<\/span> '), ~( <span style=\"color: #3366ff;\">scale<\/span> (.) %&gt;% <span style=\"color: #3366ff;\">as.vector<\/span> ))\ndf3\n\n          var1 var2 var3\n1 -0.90606801 -1.3045574 35.845273\n2 -0.56830963 -1.4133223 12.000703\n3 0.06760377 0.4739961 26.505234\n4 1.13001072 -0.6459703 9.143318\n5 -1.10827188 0.7801967 13.818282\n6 1.09890684 -0.2259798 17.741765\n7 1.24554014 0.5871157 5.441881\n8 0.34621281 1.6012242 17.618803\n9 0.24583830 -0.6610127 33.699798\n10 -1.55146305 0.8083098 16.231517<\/strong><\/pre>\n<h2> <span style=\"color: #000000;\"><strong>Standardizzare tutte le variabili<\/strong><\/span><\/h2>\n<p> <span style=\"color: #000000;\">Il codice seguente mostra come ridimensionare <em>tutte<\/em> le variabili in un frame di dati utilizzando la funzione <strong>mutate_all<\/strong> :<\/span><\/p>\n<pre style=\"background-color: #ececec; font-size: 15px;\"> <strong><span style=\"color: #993300;\">library<\/span> (dplyr)\n\n<span style=\"color: #008080;\">#make this example reproducible<\/span> \nset.seed(1)\n\n<span style=\"color: #008080;\">#create original data frame\n<\/span>df &lt;- data.frame(var1= runif(10, 0, 50), \n                 var2= runif(10, 2, 23),\n                 var3= runif(10, 5, 38))\n\n<span style=\"color: #008080;\">#scale all variables to have mean = 0 and standard deviation = 1<\/span>\ndf4 &lt;- df %&gt;% <span style=\"color: #3366ff;\">mutate_all<\/span> (~( <span style=\"color: #3366ff;\">scale<\/span> (.) %&gt;% <span style=\"color: #3366ff;\">as.vector<\/span> ))\ndf4\n\n          var1 var2 var3\n1 -0.90606801 -1.3045574 1.6819976\n2 -0.56830963 -1.4133223 -0.6715858\n3 0.06760377 0.4739961 0.7600871\n4 1.13001072 -0.6459703 -0.9536246\n5 -1.10827188 0.7801967 -0.4921813\n6 1.09890684 -0.2259798 -0.1049130\n7 1.24554014 0.5871157 -1.3189757\n8 0.34621281 1.6012242 -0.1170501\n9 0.24583830 -0.6610127 1.4702281\n10 -1.55146305 0.8083098 -0.2539824<\/strong><\/pre>\n<h2> <span style=\"color: #000000;\"><strong>Risorse addizionali<\/strong><\/span><\/h2>\n<p> <span style=\"color: #000000;\">I seguenti tutorial spiegano come eseguire altre attivit\u00e0 comuni in R:<\/span><\/p>\n<p> <a href=\"https:\/\/statorials.org\/it\/come-normalizzare-i-dati-in-r\/\" target=\"_blank\" rel=\"noopener noreferrer\">Come normalizzare i dati in R<\/a><br \/> <a href=\"https:\/\/statorials.org\/it\/deviazione-standard-in-r\/\" target=\"_blank\" rel=\"noopener noreferrer\">Come calcolare la deviazione standard in R<\/a><br \/> <a href=\"https:\/\/statorials.org\/it\/imputare-i-valori-mancanti-in-r\/\" target=\"_blank\" rel=\"noopener noreferrer\">Come imputare tutti i valori mancanti in R<\/a><br \/> <a href=\"https:\/\/statorials.org\/it\/trasformare-i-dati-in-r\/\" target=\"_blank\" rel=\"noopener noreferrer\">Come trasformare i dati in R (log, radice quadrata, radice cubica)<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Standardizzare un set di dati significa ridimensionare tutti i valori nel set di dati in modo tale che il valore medio sia 0 e la deviazione standard sia 1. Il modo pi\u00f9 comune per farlo \u00e8 utilizzare la standardizzazione del punteggio z, che scala i valori utilizzando la seguente formula: (x i \u2013 x ) [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[11],"tags":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v21.5 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>Come standardizzare i dati in R (con esempi) \u2013 Statorials<\/title>\n<meta name=\"description\" content=\"Questo tutorial spiega come standardizzare i dati in R, con diversi esempi.\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/statorials.org\/it\/normalizzare-i-dati-in-r\/\" \/>\n<meta property=\"og:locale\" content=\"it_IT\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Come standardizzare i dati in R (con esempi) \u2013 Statorials\" \/>\n<meta property=\"og:description\" content=\"Questo tutorial spiega come standardizzare i dati in R, con diversi esempi.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/statorials.org\/it\/normalizzare-i-dati-in-r\/\" \/>\n<meta property=\"og:site_name\" content=\"Statorials\" \/>\n<meta property=\"article:published_time\" content=\"2023-07-27T14:52:53+00:00\" \/>\n<meta name=\"author\" content=\"Benjamin anderson\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"Benjamin anderson\" \/>\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"2 minuti\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"WebPage\",\"@id\":\"https:\/\/statorials.org\/it\/normalizzare-i-dati-in-r\/\",\"url\":\"https:\/\/statorials.org\/it\/normalizzare-i-dati-in-r\/\",\"name\":\"Come standardizzare i dati in R (con esempi) \u2013 Statorials\",\"isPartOf\":{\"@id\":\"https:\/\/statorials.org\/it\/#website\"},\"datePublished\":\"2023-07-27T14:52:53+00:00\",\"dateModified\":\"2023-07-27T14:52:53+00:00\",\"author\":{\"@id\":\"https:\/\/statorials.org\/it\/#\/schema\/person\/0896f191fb9fb019f2cd8623112cb3ae\"},\"description\":\"Questo tutorial spiega come standardizzare i dati in R, con diversi esempi.\",\"breadcrumb\":{\"@id\":\"https:\/\/statorials.org\/it\/normalizzare-i-dati-in-r\/#breadcrumb\"},\"inLanguage\":\"it-IT\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\/\/statorials.org\/it\/normalizzare-i-dati-in-r\/\"]}]},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\/\/statorials.org\/it\/normalizzare-i-dati-in-r\/#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Casa\",\"item\":\"https:\/\/statorials.org\/it\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"Come standardizzare i dati in r: con esempi\"}]},{\"@type\":\"WebSite\",\"@id\":\"https:\/\/statorials.org\/it\/#website\",\"url\":\"https:\/\/statorials.org\/it\/\",\"name\":\"Statorials\",\"description\":\"La tua guida all&#039;alfabetizzazione statistica!\",\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":{\"@type\":\"EntryPoint\",\"urlTemplate\":\"https:\/\/statorials.org\/it\/?s={search_term_string}\"},\"query-input\":\"required name=search_term_string\"}],\"inLanguage\":\"it-IT\"},{\"@type\":\"Person\",\"@id\":\"https:\/\/statorials.org\/it\/#\/schema\/person\/0896f191fb9fb019f2cd8623112cb3ae\",\"name\":\"Benjamin anderson\",\"image\":{\"@type\":\"ImageObject\",\"inLanguage\":\"it-IT\",\"@id\":\"https:\/\/statorials.org\/it\/#\/schema\/person\/image\/\",\"url\":\"https:\/\/statorials.org\/it\/wp-content\/uploads\/2023\/10\/Dr.-Benjamin-Anderson-96x96.jpg\",\"contentUrl\":\"https:\/\/statorials.org\/it\/wp-content\/uploads\/2023\/10\/Dr.-Benjamin-Anderson-96x96.jpg\",\"caption\":\"Benjamin anderson\"},\"description\":\"Ciao, sono Benjamin, un professore di statistica in pensione diventato insegnante dedicato di Statorials. 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