{"action":"created","issue":{"url":"https://api.github.com/repos/maths/moodle-qtype_stack/issues/242","repository_url":"https://api.github.com/repos/maths/moodle-qtype_stack","labels_url":"https://api.github.com/repos/maths/moodle-qtype_stack/issues/242/labels{/name}","comments_url":"https://api.github.com/repos/maths/moodle-qtype_stack/issues/242/comments","events_url":"https://api.github.com/repos/maths/moodle-qtype_stack/issues/242/events","html_url":"https://github.com/maths/moodle-qtype_stack/issues/242","id":180553224,"number":242,"title":"Odd Rounding Feedback","user":{"login":"jmbragg","id":4606870,"avatar_url":"https://avatars.githubusercontent.com/u/4606870?v=3","gravatar_id":"","url":"https://api.github.com/users/jmbragg","html_url":"https://github.com/jmbragg","followers_url":"https://api.github.com/users/jmbragg/followers","following_url":"https://api.github.com/users/jmbragg/following{/other_user}","gists_url":"https://api.github.com/users/jmbragg/gists{/gist_id}","starred_url":"https://api.github.com/users/jmbragg/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/jmbragg/subscriptions","organizations_url":"https://api.github.com/users/jmbragg/orgs","repos_url":"https://api.github.com/users/jmbragg/repos","events_url":"https://api.github.com/users/jmbragg/events{/privacy}","received_events_url":"https://api.github.com/users/jmbragg/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"assignees":[],"milestone":null,"comments":15,"created_at":"2016-10-03T02:35:54Z","updated_at":"2016-10-14T20:27:51Z","closed_at":null,"body":"![weird rounding feedback](https://cloud.githubusercontent.com/assets/4606870/19026155/5737be38-88f0-11e6-9b1b-7e264e2372b1.PNG)\r\n\r\nCan you tell me what triggers the \"The accuracy of your answer is not correct. Either you have not rounded correctly, or you have rounded an intermediate answer which propagates an error.\" part of this feedback message?  Its confusing students in scenarios similar to this one because they think they've got the answer correct, except for the rounding when in reality they're just wrong."},"comment":{"url":"https://api.github.com/repos/maths/moodle-qtype_stack/issues/comments/253910961","html_url":"https://github.com/maths/moodle-qtype_stack/issues/242#issuecomment-253910961","issue_url":"https://api.github.com/repos/maths/moodle-qtype_stack/issues/242","id":253910961,"user":{"login":"jmbragg","id":4606870,"avatar_url":"https://avatars.githubusercontent.com/u/4606870?v=3","gravatar_id":"","url":"https://api.github.com/users/jmbragg","html_url":"https://github.com/jmbragg","followers_url":"https://api.github.com/users/jmbragg/followers","following_url":"https://api.github.com/users/jmbragg/following{/other_user}","gists_url":"https://api.github.com/users/jmbragg/gists{/gist_id}","starred_url":"https://api.github.com/users/jmbragg/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/jmbragg/subscriptions","organizations_url":"https://api.github.com/users/jmbragg/orgs","repos_url":"https://api.github.com/users/jmbragg/repos","events_url":"https://api.github.com/users/jmbragg/events{/privacy}","received_events_url":"https://api.github.com/users/jmbragg/received_events","type":"User","site_admin":false},"created_at":"2016-10-14T20:27:51Z","updated_at":"2016-10-14T20:27:51Z","body":"Well I've stayed out of this because I've been busy this week.  I think it would be a bad idea to suddenly start enforcing the 100 = 1sigfig interpretation.  That is certainly not a consistent rule here in the US.  I just took a quick peek at 4 different introductory chemistry texts that are popular and all of them said that the number of sigfigs in 100 was ambiguous and that the meaning was unclear.  Several were clear that it should only be 1 sigfig but said as a practical matter it would be assumed to be ambiguous.  \r\n\r\nThere is also the issue of \"100.\".  That's a typical way of saying, this has exactly 3 sigfigs.  Is that going to be included?\r\n\r\nI say all of this to say, I'm perfectly happy with some degree of generosity in the sigfigs test.  Sigfigs are a useful tool, because they're quick and easy and give decent answers.  They're not the exact right answer on how to do error propagation though. So I think its silly to get overly picky about how exact we're being with applying the rules of our approximation technique.\r\n\r\nThe wars over sigfigs in the chemistry world are real.  Its best to leave it generous to provide the most use for the most people.\r\n\r\nMatti, those rules for addition and subtraction are the ones that I've always seen too.  But they're also a good example of why sigfigs as a general rule are just an approximation.  After all, why should 3.00+3.00+3.00+3.00 = 12.00 when 3.00*4.0000000000000000000 = 12.0"}}
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