{"id":1675,"date":"2023-07-25T10:29:02","date_gmt":"2023-07-25T10:29:02","guid":{"rendered":"https:\/\/statorials.org\/pt\/margem-de-erro-vs-intervalo-de-confianca\/"},"modified":"2023-07-25T10:29:02","modified_gmt":"2023-07-25T10:29:02","slug":"margem-de-erro-vs-intervalo-de-confianca","status":"publish","type":"post","link":"https:\/\/statorials.org\/pt\/margem-de-erro-vs-intervalo-de-confianca\/","title":{"rendered":"Margem de erro e intervalo de confian\u00e7a: qual a diferen\u00e7a?"},"content":{"rendered":"<p><\/p>\n<hr>\n<p><span style=\"color: #000000;\">Freq\u00fcentemente, nas estat\u00edsticas, usamos <a href=\"https:\/\/statorials.org\/pt\/intervalos-de-confianca\/\" target=\"_blank\" rel=\"noopener\">intervalos de confian\u00e7a<\/a> para estimar o valor de um <a href=\"https:\/\/statorials.org\/pt\/estatisticas-vs-parametro\/\" target=\"_blank\" rel=\"noopener\">par\u00e2metro populacional<\/a> com um certo n\u00edvel de confian\u00e7a.<\/span><\/p>\n<p> <span style=\"color: #000000;\">Cada intervalo de confian\u00e7a assume a seguinte forma:<\/span><\/p>\n<p> <span style=\"color: #000000;\">Intervalo de confian\u00e7a = [limite inferior, limite superior]<\/span><\/p>\n<p> <span style=\"color: #000000;\">A <strong>margem de erro<\/strong> \u00e9 igual \u00e0 metade da largura de todo o intervalo de confian\u00e7a.<\/span><\/p>\n<p> <span style=\"color: #000000;\">Por exemplo, suponha que temos o seguinte intervalo de confian\u00e7a para uma m\u00e9dia populacional:<\/span><\/p>\n<p> <span style=\"color: #000000;\">Intervalo de confian\u00e7a de 95% = [12,5, 18,5]<\/span><\/p>\n<p> <span style=\"color: #000000;\">A largura do intervalo de confian\u00e7a \u00e9 18,5 \u2013 12,5 = 6.<\/span> <span style=\"color: #000000;\">A margem de erro \u00e9 metade da largura, o que seria 6\/2 = <strong>3<\/strong> .<\/span><\/p>\n<p> <span style=\"color: #000000;\">Os exemplos a seguir mostram como calcular um intervalo de confian\u00e7a e a margem de erro para v\u00e1rios cen\u00e1rios diferentes.<\/span><\/p>\n<h3> <span style=\"color: #000000;\"><strong>Exemplo 1: Intervalo de confian\u00e7a e margem de erro para a m\u00e9dia populacional<\/strong><\/span><\/h3>\n<p> <span style=\"color: #000000;\">Usamos a seguinte f\u00f3rmula para calcular um intervalo de confian\u00e7a para uma m\u00e9dia populacional:<\/span><\/p>\n<p> <span style=\"color: #000000;\"><strong>Intervalo de confian\u00e7a = <span style=\"text-decoration: overline;\">x<\/span> +\/- z*(s\/\u221a <span style=\"border-top: 1px solid black;\">n<\/span> )<\/strong><\/span><\/p>\n<p> <span style=\"color: #000000;\">Ouro:<\/span><\/p>\n<ul>\n<li> <span style=\"color: #000000;\"><strong><span style=\"text-decoration: overline;\">x<\/span> :<\/strong> m\u00e9dias amostrais<\/span><\/li>\n<li> <span style=\"color: #000000;\"><strong>z:<\/strong> o valor z-cr\u00edtico<\/span><\/li>\n<li> <span style=\"color: #000000;\"><strong>s:<\/strong> desvio padr\u00e3o da amostra<\/span><\/li>\n<li> <span style=\"color: #000000;\"><strong>n:<\/strong> tamanho da amostra<\/span><\/li>\n<\/ul>\n<p> <span style=\"color: #000000;\"><strong>Exemplo:<\/strong> Suponha que coletamos uma amostra aleat\u00f3ria de golfinhos com as seguintes informa\u00e7\u00f5es:<\/span><\/p>\n<ul>\n<li> <span style=\"color: #000000;\">Tamanho da amostra <strong>n = 40<\/strong><\/span><\/li>\n<li> <span style=\"color: #000000;\">Peso m\u00e9dio da amostra <strong><span style=\"text-decoration: overline;\">x<\/span> = 300<\/strong><\/span><\/li>\n<li> <span style=\"color: #000000;\">Desvio padr\u00e3o amostral <strong>s = 18,5<\/strong><\/span><\/li>\n<\/ul>\n<p> <span style=\"color: #000000;\"><span style=\"color: #000000;\">Podemos inserir esses n\u00fameros na <a href=\"https:\/\/statorials.org\/pt\/calculadora-de-intervalo-de-confianca-medio\/\" target=\"_blank\" rel=\"noopener\">calculadora do intervalo de confian\u00e7a<\/a> para encontrar o intervalo de confian\u00e7a de 95%:<\/span><\/span> <\/p>\n<p><img decoding=\"async\" loading=\"lazy\" class=\" wp-image-16510 aligncenter\" src=\"https:\/\/statorials.org\/wp-content\/uploads\/2023\/08\/mar1.png\" alt=\"\" width=\"352\" height=\"439\" srcset=\"\" sizes=\"auto, \"><\/p>\n<p> <span style=\"color: #000000;\">O intervalo de confian\u00e7a de 95% para o verdadeiro peso m\u00e9dio da popula\u00e7\u00e3o de tartarugas \u00e9 <strong>[294,267, 305,733]<\/strong> .<\/span><\/p>\n<p> <span style=\"color: #000000;\">A margem de erro seria igual \u00e0 metade da largura do intervalo de confian\u00e7a, ou seja:<\/span><\/p>\n<p> <span style=\"color: #000000;\">Margem de erro: (305,733 \u2013 294,267) \/ 2 = <strong>5,733<\/strong> .<\/span><\/p>\n<h3> <span style=\"color: #000000;\"><strong>Exemplo 2: Intervalo de confian\u00e7a e margem de erro para propor\u00e7\u00e3o populacional<\/strong><\/span><\/h3>\n<p> <span style=\"color: #000000;\">Usamos a seguinte f\u00f3rmula para calcular um intervalo de confian\u00e7a para uma propor\u00e7\u00e3o populacional:<\/span><\/p>\n<p> <span style=\"color: #000000;\"><strong>Intervalo de confian\u00e7a = p<\/strong> <strong>+\/- z*(\u221a <span style=\"text-decoration: overline;\">p(1-p) \/ n<\/span> )<\/strong><\/span><\/p>\n<p> <span style=\"color: #000000;\">Ouro:<\/span><\/p>\n<ul>\n<li> <span style=\"color: #000000;\"><strong>p:<\/strong> propor\u00e7\u00e3o da amostra<\/span><\/li>\n<li> <span style=\"color: #000000;\"><strong>z:<\/strong> o valor z escolhido<\/span><\/li>\n<li> <span style=\"color: #000000;\"><strong>n:<\/strong> tamanho da amostra<\/span><\/li>\n<\/ul>\n<p> <span style=\"color: #000000;\"><strong>Exemplo:<\/strong> Suponha que queiramos estimar a propor\u00e7\u00e3o de residentes num condado que s\u00e3o a favor de uma determinada lei. Selecionamos uma amostra aleat\u00f3ria de 100 residentes e perguntamos qual \u00e9 a sua posi\u00e7\u00e3o em rela\u00e7\u00e3o \u00e0 lei. Aqui est\u00e3o os resultados:<\/span><\/p>\n<ul>\n<li> <span style=\"color: #000000;\">Tamanho da amostra <strong>n = 100<\/strong><\/span><\/li>\n<li> <span style=\"color: #000000;\">Propor\u00e7\u00e3o a favor da lei <strong>p = 0,56<\/strong><\/span><\/li>\n<\/ul>\n<p> <span style=\"color: #000000;\">Podemos inserir esses n\u00fameros no <a href=\"https:\/\/statorials.org\/pt\/calculadora-de-proporcao-de-intervalo-de-confianca\/\" target=\"_blank\" rel=\"noopener\">intervalo de confian\u00e7a de uma calculadora de propor\u00e7\u00e3o<\/a> para encontrar o intervalo de confian\u00e7a de 95%:<\/span> <\/p>\n<p><img decoding=\"async\" loading=\"lazy\" class=\" wp-image-16513 aligncenter\" src=\"https:\/\/statorials.org\/wp-content\/uploads\/2023\/08\/mar2.png\" alt=\"\" width=\"365\" height=\"384\" srcset=\"\" sizes=\"auto, \"><\/p>\n<p> <span style=\"color: #000000;\">O intervalo de confian\u00e7a de 95% para a verdadeira propor\u00e7\u00e3o da popula\u00e7\u00e3o \u00e9 <strong>[0,4627, 0,6573]<\/strong> .<\/span><\/p>\n<p> <span style=\"color: #000000;\">A margem de erro seria igual \u00e0 metade da largura do intervalo de confian\u00e7a, ou seja:<\/span><\/p>\n<p> <span style=\"color: #000000;\">Margem de erro: (0,6573 \u2013 0,4627) \/ 2 = <strong>0,0973<\/strong> .<\/span><\/p>\n<h3> <span style=\"color: #000000;\"><strong>Recursos adicionais<\/strong><\/span><\/h3>\n<p> <a href=\"https:\/\/statorials.org\/pt\/margem-de-erro-vs-erro-padrao-qual-e-a-diferenca\/\" target=\"_blank\" rel=\"noopener\">Margem de erro versus erro padr\u00e3o: qual a diferen\u00e7a?<\/a><br \/> Como encontrar margem de erro no Excel<br \/> <a href=\"https:\/\/statorials.org\/pt\/margem-de-erro-ti-84\/\" target=\"_blank\" rel=\"noopener\">Como encontrar a margem de erro em uma calculadora TI-84<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Freq\u00fcentemente, nas estat\u00edsticas, usamos intervalos de confian\u00e7a para estimar o valor de um par\u00e2metro populacional com um certo n\u00edvel de confian\u00e7a. Cada intervalo de confian\u00e7a assume a seguinte forma: Intervalo de confian\u00e7a = [limite inferior, limite superior] A margem de erro \u00e9 igual \u00e0 metade da largura de todo o intervalo de confian\u00e7a. Por exemplo, [&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":[],"class_list":["post-1675","post","type-post","status-publish","format-standard","hentry","category-guia"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v21.5 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>Margem de erro e intervalo de confian\u00e7a: qual a diferen\u00e7a?<\/title>\n<meta name=\"description\" content=\"Este tutorial explica a diferen\u00e7a entre margem de erro e intervalo de confian\u00e7a, com exemplos.\" \/>\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\/pt\/margem-de-erro-vs-intervalo-de-confianca\/\" \/>\n<meta property=\"og:locale\" content=\"pt_PT\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Margem de erro e intervalo de confian\u00e7a: qual a diferen\u00e7a?\" \/>\n<meta property=\"og:description\" content=\"Este tutorial explica a diferen\u00e7a entre margem de erro e intervalo de confian\u00e7a, com exemplos.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/statorials.org\/pt\/margem-de-erro-vs-intervalo-de-confianca\/\" \/>\n<meta property=\"og:site_name\" content=\"Statorials\" \/>\n<meta property=\"article:published_time\" content=\"2023-07-25T10:29:02+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/statorials.org\/wp-content\/uploads\/2023\/08\/mar1.png\" \/>\n<meta name=\"author\" content=\"Dr. benjamim anderson\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Escrito por\" \/>\n\t<meta name=\"twitter:data1\" content=\"Dr. benjamim anderson\" \/>\n\t<meta name=\"twitter:label2\" content=\"Tempo estimado de leitura\" \/>\n\t<meta name=\"twitter:data2\" content=\"2 minutos\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"WebPage\",\"@id\":\"https:\/\/statorials.org\/pt\/margem-de-erro-vs-intervalo-de-confianca\/\",\"url\":\"https:\/\/statorials.org\/pt\/margem-de-erro-vs-intervalo-de-confianca\/\",\"name\":\"Margem de erro e intervalo de confian\u00e7a: qual a diferen\u00e7a?\",\"isPartOf\":{\"@id\":\"https:\/\/statorials.org\/pt\/#website\"},\"datePublished\":\"2023-07-25T10:29:02+00:00\",\"dateModified\":\"2023-07-25T10:29:02+00:00\",\"author\":{\"@id\":\"https:\/\/statorials.org\/pt\/#\/schema\/person\/e08f98e8db95e0aa9c310e1b27c9c666\"},\"description\":\"Este tutorial explica a diferen\u00e7a entre margem de erro e intervalo de confian\u00e7a, com exemplos.\",\"breadcrumb\":{\"@id\":\"https:\/\/statorials.org\/pt\/margem-de-erro-vs-intervalo-de-confianca\/#breadcrumb\"},\"inLanguage\":\"pt-PT\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\/\/statorials.org\/pt\/margem-de-erro-vs-intervalo-de-confianca\/\"]}]},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\/\/statorials.org\/pt\/margem-de-erro-vs-intervalo-de-confianca\/#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Lar\",\"item\":\"https:\/\/statorials.org\/pt\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"Margem de erro e intervalo de confian\u00e7a: qual a diferen\u00e7a?\"}]},{\"@type\":\"WebSite\",\"@id\":\"https:\/\/statorials.org\/pt\/#website\",\"url\":\"https:\/\/statorials.org\/pt\/\",\"name\":\"Statorials\",\"description\":\"O seu guia para a literacia estat\u00edstica!\",\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":{\"@type\":\"EntryPoint\",\"urlTemplate\":\"https:\/\/statorials.org\/pt\/?s={search_term_string}\"},\"query-input\":\"required name=search_term_string\"}],\"inLanguage\":\"pt-PT\"},{\"@type\":\"Person\",\"@id\":\"https:\/\/statorials.org\/pt\/#\/schema\/person\/e08f98e8db95e0aa9c310e1b27c9c666\",\"name\":\"Dr. benjamim anderson\",\"image\":{\"@type\":\"ImageObject\",\"inLanguage\":\"pt-PT\",\"@id\":\"https:\/\/statorials.org\/pt\/#\/schema\/person\/image\/\",\"url\":\"https:\/\/statorials.org\/pt\/wp-content\/uploads\/2023\/10\/Dr.-Benjamin-Anderson-96x96.jpg\",\"contentUrl\":\"https:\/\/statorials.org\/pt\/wp-content\/uploads\/2023\/10\/Dr.-Benjamin-Anderson-96x96.jpg\",\"caption\":\"Dr. benjamim anderson\"},\"description\":\"Ol\u00e1, sou Benjamin, um professor aposentado de estat\u00edstica que se tornou professor dedicado na Statorials. 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