tag:blogger.com,1999:blog-6894866515532737257.post2359903811026635882..comments2017-07-27T07:46:01.067-07:00Comments on Probably Overthinking It: A nice Bayes theorem problem: medical testingAllen Downeyhttps://plus.google.com/111942648516576371054noreply@blogger.comBlogger7125tag:blogger.com,1999:blog-6894866515532737257.post-33939553486119102182017-04-04T10:58:50.167-07:002017-04-04T10:58:50.167-07:00Hi Riya,
Not sure if you are still checking this b...Hi Riya,<br />Not sure if you are still checking this blog, but the computational error in the answer of the MIT course is just confined to the labels of two branches (test1, disease absent). They switched the labels with the probs of test1 detecting or not detecting the disease. However, the final probs at the leafs of their table are correct (they assume proper labels in their computations). And once those are correct, then the answer is in fact identical to 5/13 (as they report). <br /><br />Long story short, the results of the MIT course and the results presented here are identical, they are both correct, and the only mistake is the wrong label on two branches. <br /><br />And finally, I punched these numbers in the Netica program (not that it's really needed beyond the worksheet), and also get the correct 5/13 answer. Unfortunately I don't know how to share Netica worksheets in blog post, otherwise I would post it...Felix Thoemmeshttps://www.blogger.com/profile/02139944750643002756noreply@blogger.comtag:blogger.com,1999:blog-6894866515532737257.post-6617413490974662692017-02-18T17:26:27.722-08:002017-02-18T17:26:27.722-08:00I have a question though. I mentioned that this qu...I have a question though. I mentioned that this question was taken from the MIT 2006 OCW final exam for computer science. The solution was also available on the internet. Even though they have mentioned the answer to be 5/13 I.e. 10/26 but there's some calculation error in their method. The correct answer according to their method is 25/63. But I really don't understand why they did the question that way. I'm adding the links to both the question and the answer here. It's the fourth question. <br /><a href="https://www.google.co.in/url?sa=t&source=web&rct=j&url=https://ocw.mit.edu/courses/electrical-engineering-and-computer-science/6-042j-mathematics-for-computer-science-fall-2010/exams/MIT6_042JF10_fnl_2006_sol.pdf&ved=0ahUKEwiWmOT3-5rSAhVCpo8KHbR6DbMQFgglMAA&usg=AFQjCNGh_rIRn7AyI4WO9Paj9m-iq_riUw&sig2=ZbyrZqKgd6YJaSjmAEWhIg" rel="nofollow">answer</a><br /><a href="https://www.google.co.in/url?sa=t&source=web&rct=j&url=https://ocw.mit.edu/courses/electrical-engineering-and-computer-science/6-042j-mathematics-for-computer-science-fall-2010/exams/MIT6_042JF10_final_2006.pdf&ved=0ahUKEwiWmOT3-5rSAhVCpo8KHbR6DbMQFggoMAE&usg=AFQjCNGfuqKhxH7H6Wpbt4nB9DjAWN4JvA&sig2=GmFaDfgVkq0T3cb3O3BeuA" rel="nofollow">question</a><br />Riyahttps://www.blogger.com/profile/05095295993427070799noreply@blogger.comtag:blogger.com,1999:blog-6894866515532737257.post-12877653335172783042017-02-18T10:34:12.984-08:002017-02-18T10:34:12.984-08:00This comment has been removed by the author.Riyahttps://www.blogger.com/profile/05095295993427070799noreply@blogger.comtag:blogger.com,1999:blog-6894866515532737257.post-78346079788040356192017-02-17T12:24:31.688-08:002017-02-17T12:24:31.688-08:00I have corrected that error. Thanks!I have corrected that error. Thanks!Allen Downeyhttps://www.blogger.com/profile/01633071333405221858noreply@blogger.comtag:blogger.com,1999:blog-6894866515532737257.post-14487104130235535242017-02-17T10:13:13.953-08:002017-02-17T10:13:13.953-08:00I enjoyed the problem, but I got a different answe...I enjoyed the problem, but I got a different answer. I thought the prior for TEST1 was 2/3.David Bodyhttps://www.blogger.com/profile/09987602296796651688noreply@blogger.comtag:blogger.com,1999:blog-6894866515532737257.post-20559111740998241692017-02-17T07:26:52.253-08:002017-02-17T07:26:52.253-08:00Thanks for letting me know about the source of the...Thanks for letting me know about the source of the problem. If you have a link, I'll include it in the article.Allen Downeyhttps://www.blogger.com/profile/01633071333405221858noreply@blogger.comtag:blogger.com,1999:blog-6894866515532737257.post-69936903023640887172017-02-17T07:16:54.521-08:002017-02-17T07:16:54.521-08:00Hey thanks Mr. Allen for taking up the question.I ...Hey thanks Mr. Allen for taking up the question.I would just like to mention that I came across this question from the MIT OCW final exam for computer science.<br />I have thought of two approaches and of course they're giving different answers, although I'm a little biased towards one of the approaches. I would be really glad if I could finally understand what's happening in this question. Riyahttps://www.blogger.com/profile/05095295993427070799noreply@blogger.com