{"id":711,"date":"2013-09-12T20:22:37","date_gmt":"2013-09-12T19:22:37","guid":{"rendered":"https:\/\/blogs.bmj.com\/adc\/?p=711"},"modified":"2013-09-09T20:32:55","modified_gmt":"2013-09-09T19:32:55","slug":"statsminiblog-type-i-and-ii-errors","status":"publish","type":"post","link":"https:\/\/blogs.bmj.com\/adc\/2013\/09\/12\/statsminiblog-type-i-and-ii-errors\/","title":{"rendered":"StatsMiniBlog: Type I and II errors"},"content":{"rendered":"<p><a href=\"https:\/\/blogs.bmj.com\/adc\/files\/2013\/08\/Image78.gif\"><img loading=\"lazy\" decoding=\"async\" class=\"alignleft size-full wp-image-674\" alt=\"StatsMiniBlog\" src=\"https:\/\/blogs.bmj.com\/adc\/files\/2013\/08\/Image78.gif\" width=\"180\" height=\"76\" \/><\/a>After reading the title, most people now feel vaguely nauseous. If you throw in alpha and beta, or worse\u00a0\u03b1 and\u00a0\u03b2, then there&#8217;s a distinctly bilious taste.<\/p>\n<p>Don&#8217;t get sick, though. Take a deep breath and fall back on what you already know:<!--more--><\/p>\n<p>Type I error = calling a difference &#8216;real&#8217; when it isn&#8217;t. This is what we look at with p-values and set, conventionally, at 0.05 == 5%<\/p>\n<p>Type II error = calling something the same when there really is a difference. This is &#8216;power&#8217;, and is conventionally 80% (ie 20% of the time we&#8217;ll accept a result that says &#8220;no difference&#8221; when in truth, there is).<\/p>\n<p>We can actually assess both elements when we look at a confidence interval. If it&#8217;s a 95% CI, then we see if it crosses the line of no effect (0 for absolutes, 1 for ratios). And if it does, we can assess if the study gives us a fair guess it&#8217;s too uncertain to tell us much, or if it&#8217;s close enough to tell us there is no difference &#8211; as we <a title=\"It\u2019s all the same\" href=\"https:\/\/blogs.bmj.com\/adc\/2012\/01\/23\/its-all-the-same\/\">discussed previously<\/a>.<\/p>\n<p>Stats isn&#8217;t really hard. Just if you put anything in Greek, it seems\u00a0\u03b4\u03cd\u03c3\u03ba\u03bf\u03bb\u03bf\u03c2<\/p>\n<p>&#8211; Archi<!--TrendMD v2.4.8--><\/p>\n","protected":false},"excerpt":{"rendered":"<p>After reading the title, most people now feel vaguely nauseous. If you throw in alpha and beta, or worse\u00a0\u03b1 and\u00a0\u03b2, then there&#8217;s a distinctly bilious taste. Don&#8217;t get sick, though. Take a deep breath and fall back on what you already know: [&#8230;]<\/p>\n<p><a class=\"btn btn-secondary understrap-read-more-link\" href=\"https:\/\/blogs.bmj.com\/adc\/2013\/09\/12\/statsminiblog-type-i-and-ii-errors\/\">Read More&#8230;<\/a><\/p>\n","protected":false},"author":7,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2676],"tags":[],"class_list":["post-711","post","type-post","status-publish","format-standard","hentry","category-stats"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.3 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>StatsMiniBlog: Type I and II errors - ADC Online Blog<\/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.bmj.com\/adc\/2013\/09\/12\/statsminiblog-type-i-and-ii-errors\/\" \/>\n<meta property=\"og:locale\" content=\"en_GB\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"StatsMiniBlog: Type I and II errors - ADC Online Blog\" \/>\n<meta property=\"og:description\" content=\"After reading the title, most people now feel vaguely nauseous. If you throw in alpha and beta, or worse\u00a0\u03b1 and\u00a0\u03b2, then there&#8217;s a distinctly bilious taste. Don&#8217;t get sick, though. 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