{"id":1512,"date":"2022-09-03T13:17:06","date_gmt":"2022-09-03T13:17:06","guid":{"rendered":"http:\/\/www.wellformedness.com\/blog\/?p=1512"},"modified":"2022-09-05T13:23:47","modified_gmt":"2022-09-05T13:23:47","slug":"on-significance-levels","status":"publish","type":"post","link":"https:\/\/www.wellformedness.com\/blog\/on-significance-levels\/","title":{"rendered":"On “significance levels”"},"content":{"rendered":"

R (I think it was R) introduced a practice in which multiple asterisk characters are used to indicate different significance levels<\/em> for tests. [Correction: Bill Idsardi points out some prior art that probably predates the R convention. I have no idea what S or S-Plus did, nor what R was like before 2006 or so. But certainly R has helped popularize it.] <\/strong>For instance, in R statistical summaries, * denotes a p<\/em>-value such that .01 < p<\/em> < .05, ** denotes a p-value such that .001 < p<\/em> < .01, and *** denotes a p<\/em>-value < .001. This type of reporting increasingly can be found in papers also, but there are good reasons not to copy R’s bad behavior.<\/p>\n

In null hypothesis testing, the mere size of the p<\/em>-value itself has no meaning. All that matters is whether\u00a0p<\/em> is greater than or less than the \u03b1-level. Depending on space, we may report the exact value of\u00a0p<\/em> for a test (often rounded to two digits and “<<\/em> .01″ used for abbreviatory purposes, since you don’t want to round down here), but we need not. And it simply does not matter at all how small\u00a0p<\/em> is when it’s less than the \u03b1-level. There is no notion of “more significant” or “less significant”.<\/p>\n

R also uses the period character ‘.’ is used to indicate a p-<\/em>value between .05 and .1. Of course, I have never read a single study using an \u03b1-level greater than .05 (I suppose this would simply make the possibility of Type I error too high), so I’m not sure what the point is.<\/p>\n

My suggestion here is simple. If you want, use ‘*’ to indicate a significant (p < \u03b1<\/em>) result, and then in the caption write something like “*:\u00a0p\u00a0<\/em>< .05″ (assuming that your \u03b1-<\/em>level is .05). Do not use additional asterisks.<\/p>\n","protected":false},"excerpt":{"rendered":"

R (I think it was R) introduced a practice in which multiple asterisk characters are used to indicate different significance levels for tests. [Correction: Bill Idsardi points out some prior art that probably predates the R convention. I have no idea what S or S-Plus did, nor what R was like before 2006 or so. … Continue reading “On “significance levels””<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_crdt_document":"","footnotes":""},"categories":[4,7],"tags":[],"class_list":["post-1512","post","type-post","status-publish","format-standard","hentry","category-language","category-presentation-of-self"],"_links":{"self":[{"href":"https:\/\/www.wellformedness.com\/blog\/wp-json\/wp\/v2\/posts\/1512","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.wellformedness.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.wellformedness.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.wellformedness.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.wellformedness.com\/blog\/wp-json\/wp\/v2\/comments?post=1512"}],"version-history":[{"count":3,"href":"https:\/\/www.wellformedness.com\/blog\/wp-json\/wp\/v2\/posts\/1512\/revisions"}],"predecessor-version":[{"id":1515,"href":"https:\/\/www.wellformedness.com\/blog\/wp-json\/wp\/v2\/posts\/1512\/revisions\/1515"}],"wp:attachment":[{"href":"https:\/\/www.wellformedness.com\/blog\/wp-json\/wp\/v2\/media?parent=1512"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.wellformedness.com\/blog\/wp-json\/wp\/v2\/categories?post=1512"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.wellformedness.com\/blog\/wp-json\/wp\/v2\/tags?post=1512"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}