{"id":830,"date":"2012-01-26T18:06:58","date_gmt":"2012-01-26T18:06:58","guid":{"rendered":"https:\/\/www.open.ac.uk\/blogs\/SallyJordan\/?p=830"},"modified":"2012-01-26T18:08:12","modified_gmt":"2012-01-26T18:08:12","slug":"problems-with-trigonometry-or-rounding","status":"publish","type":"post","link":"https:\/\/www.open.ac.uk\/blogs\/SallyJordan\/?p=830","title":{"rendered":"Problems with trigonometry or rounding?"},"content":{"rendered":"<p><a href=\"https:\/\/www.open.ac.uk\/blogs\/SallyJordan\/wp-content\/uploads\/2012\/01\/Capture1.png\"><img loading=\"lazy\" decoding=\"async\" class=\"alignleft size-full wp-image-831\" title=\"Capture\" src=\"https:\/\/www.open.ac.uk\/blogs\/SallyJordan\/wp-content\/uploads\/2012\/01\/Capture1.png\" alt=\"\" width=\"332\" height=\"425\" srcset=\"https:\/\/www.open.ac.uk\/blogs\/SallyJordan\/wp-content\/uploads\/2012\/01\/Capture1.png 332w, https:\/\/www.open.ac.uk\/blogs\/SallyJordan\/wp-content\/uploads\/2012\/01\/Capture1-234x300.png 234w\" sizes=\"auto, (max-width: 332px) 100vw, 332px\" \/><\/a>It is not a mistake that I start this post with a screenshot of the same variant of the same question that I was talking about last time.<\/p>\n<p>I said that 8.2% of responses got the trigonometry or the algebra wrong. The problem is that 6.2% of responses are wrong simply because they can&#8217;t round correctly.<\/p>\n<p>To five significant figures, the correct answer is 39.495 metres. As I&#8217;ve said <a href=\"https:\/\/www.open.ac.uk\/blogs\/SallyJordan\/?p=680\">before<\/a>, people seem to be very poor at rounding this sort of number. The correct answer, to the requested two significant figures, is 39 metres, but those 6.2% of responses give the answer of 40 metres.<\/p>\n<p>There are two lessons here<\/p>\n<p>1. Improve the teaching on rounding (already done);<\/p>\n<p>2. Don&#8217;t assume you know what students will do wrong in e-assessment questions. Look at real responses from real students. I don&#8217;t apologise for saying that yet again. If you don&#8217;t do this you will be left as I have been left here with a question that, for a sizeable fraction of students, is not assessing what the author (me!) intended.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>It is not a mistake that I start this post with a screenshot of the same variant of the same question that I was talking about last time. I said that 8.2% of responses got the trigonometry or the algebra &hellip; <a href=\"https:\/\/www.open.ac.uk\/blogs\/SallyJordan\/?p=830\">Continue reading <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[111],"tags":[369,161],"class_list":["post-830","post","type-post","status-publish","format-standard","hentry","category-mathematical-misunderstandings","tag-mathematical-misunderstandings","tag-rounding"],"_links":{"self":[{"href":"https:\/\/www.open.ac.uk\/blogs\/SallyJordan\/index.php?rest_route=\/wp\/v2\/posts\/830","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.open.ac.uk\/blogs\/SallyJordan\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.open.ac.uk\/blogs\/SallyJordan\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.open.ac.uk\/blogs\/SallyJordan\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.open.ac.uk\/blogs\/SallyJordan\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=830"}],"version-history":[{"count":6,"href":"https:\/\/www.open.ac.uk\/blogs\/SallyJordan\/index.php?rest_route=\/wp\/v2\/posts\/830\/revisions"}],"predecessor-version":[{"id":859,"href":"https:\/\/www.open.ac.uk\/blogs\/SallyJordan\/index.php?rest_route=\/wp\/v2\/posts\/830\/revisions\/859"}],"wp:attachment":[{"href":"https:\/\/www.open.ac.uk\/blogs\/SallyJordan\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=830"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.open.ac.uk\/blogs\/SallyJordan\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=830"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.open.ac.uk\/blogs\/SallyJordan\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=830"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}