https://www.explainxkcd.com/wiki/api.php?action=feedcontributions&user=173.245.53.137&feedformat=atomexplain xkcd - User contributions [en]2024-03-28T09:52:23ZUser contributionsMediaWiki 1.30.0https://www.explainxkcd.com/wiki/index.php?title=Talk:1347:_t_Distribution&diff=63392Talk:1347: t Distribution2014-03-26T15:05:46Z<p>173.245.53.137: Added question about joke in follow-up to Vyzen's explanation</p>
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<div>http://en.m.wikipedia.org/wiki/Student%27s_t-test<br />
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[[Special:Contributions/173.245.50.73|173.245.50.73]] 05:20, 26 March 2014 (UTC)Adam<br />
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I think this is a comment of the quality of education today - it is difficult to grade students on a distribution curve and even more so when you take into account the distribution curve of the teachers ability. {{unsigned ip|108.162.249.205}}<br />
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I noticed the teacher's curve is symmetrical, and after further inspection it could be interpreted as an edge detection: high values show where an edge occurs. The two highest peaks would nicely align with the edges of the paper, the next highest peaks fit the edges of the table, and the rest could be approximation artefacts, as they're equidistant and rather insignificant compared to those four. I'm not statistics pro, but maybe that rings someone's bells? [[Special:Contributions/108.162.210.239|108.162.210.239]] 07:56, 26 March 2014 (UTC)<br />
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:Interesting observation. It may play into an age-long legend told and re-told among the students that some teachers grade papers by tossing the whole pile in the air; those sheets that land on the teacher's desk get a pass, those falling to the floor get a fail. Sometimes the story gets modified in such a way that papers falling on the teacher's book (or other object) laying on the desk will get a higher marking than those simply hitting the desk. The latter version would explain the higher sheet-size-apart peaks. [[Special:Contributions/108.162.210.111|108.162.210.111]] 08:57, 26 March 2014 (UTC)<br />
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To be more explicit, I think the sheet of paper represents some data. Cueball is not happy with the results of applying Student's t test, so ze is trying more complex tools in the hope of getting significance. -- TimMc / [[Special:Contributions/173.245.52.27|173.245.52.27]] 11:51, 26 March 2014 (UTC)<br />
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:I would upvote this comment if allowed. As an aside, there are some teachers who think a class' grades will always fall into a nice t Distribution (thus the expression "grading on a curve") and others who vehemently hate the notion. Source: my 3-year stint as a math teacher in an urban high school. [[User:Smperron|Smperron]] ([[User talk:Smperron|talk]]) 14:06, 26 March 2014 (UTC)<br />
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Man, normally these explanations clear the comic right up for me, but I've read this one thrice now and I still can't figure out what a t-distribution is, much less a joke based on one. The only definition being a Wikipedia quote written in legalese doesn't help. So a t-distribution estimates...the probability of a population's average when there's unknown information?[[Special:Contributions/108.162.216.48|108.162.216.48]] 12:17, 26 March 2014 (UTC)<br />
:The unknown information is the sample size (class size, for example) and standard distribution (by how much, on average, is something going to vary from the mean). The unknown information is not "in the data".[[User:Jarod997|Jarod997]] ([[User talk:Jarod997|talk]]) 12:28, 26 March 2014 (UTC)<br />
:Basically, if you have an underlying process that would produce samples with a Gaussian distribution with mean of 0, and stddev of 1, and then you pull a finite number of samples out of it, and do the usual "average" operation on those samples (i.e. sum them and divide by the number of samples) you would expect that that computed average would be close to zero. But it might not be! By chance the samples you pulled might mostly have been from the far right or left side of distribution and the average you got would be way off. Student's T distribution (for a certain number of samples, n) is basically "given that the underlying process a Gaussian with mean zero and stddev of 1, if I repeatedly take n samples from that distribution and compute the average of those samples to get an "estimated mean", this is how I expect that estimated mean to be distributed". Naturally, this is important in questions like "I took 100 samples and got an average of 0.02 -- does this mean that it is sensible to think that the mean of the underlying distribution is actually zero?" <br />
: Of course, most of the joke is that the distribution is named "Student's", which is not strongly dependent on the nature of the statistics. [[User:Vyzen|Vyzen]] ([[User talk:Vyzen|talk]]) 12:42, 26 March 2014 (UTC)<br />
::Okay, it's pretty clear to me now what the Student's t distribution is. I'm still not sure about the punchline though, how does the "Teacher's" t distribution come into play? Does the uneven distribution represent any phenomena in the academic world? Like, as suggested above, is this a joke about grading? [[Special:Contributions/173.245.53.137|173.245.53.137]] 15:05, 26 March 2014 (UTC)<br />
The teacher's t-distribution looks like multiple spikier curves with different centres added together<br />
and it doesn't fit the table. [[User:Wwt|Wwt]] ([[User talk:Wwt|talk]]) 13:17, 26 March 2014 (UTC)<br />
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I took from it that the Students Distribution was too perfect, and real data would rarely yield those idealized results in a small sample size. That the teacher's distribution used actual numbers, with the occasional spikes. I took from the title text, the tendency of students, or anyone with pre-conceived notions, to keep redoing the test until they get the results they expect, in this case, the textbook result. [[Special:Contributions/173.245.55.71|173.245.55.71]] 13:25, 26 March 2014 (UTC)<br />
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Any thoughts on the piece of paper he's trying to pull out from beneath the Students' T-distribution? [[Special:Contributions/108.162.219.66|108.162.219.66]] 14:10, 26 March 2014 (UTC)</div>173.245.53.137https://www.explainxkcd.com/wiki/index.php?title=Talk:1346:_Career&diff=63281Talk:1346: Career2014-03-24T19:53:52Z<p>173.245.53.137: </p>
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<div>Come on ... those tasks can't be random ... someone find out what is Randal referring to ... isn't {{w|Luke Skywalker}} doing something wiht dryer traps at start of fourth movie? -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 11:10, 24 March 2014 (UTC)<br />
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:The answer to your question may depend upon which movie you think is the "fourth movie" (4th episode? 4th movie produced? If it's 4th movie produced, do you count the Holiday Special? Also, should anyone, anywhere, for any reason ever count the Holiday Special?) -- [[User:Brettpeirce|Brettpeirce]] ([[User talk:Brettpeirce|talk]]) 12:25, 24 March 2014 (UTC)<br />
:: Im sure he is refering to {{w|The Phantom Menace}}, and the comic could describe Anakin, however im not sure what "lump of slight soft wax" would refer to. [[User:Spongebog|Spongebog]] ([[User talk:Spongebog|talk]]) 14:49, 24 March 2014 (UTC)<br />
:::I believe Hkmaly is referring to Episode IV. However, I think he's reading too much into this, and the tasks really are random. You simply can't connect them in a way that makes sense. [[User:NealCruco|NealCruco]] ([[User talk:NealCruco|talk]]) 16:38, 24 March 2014 (UTC)<br />
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I wouldn't say "it's impossible that anyone would pay someone for peeling lint from dryer traps" as someone in the commercial laundry mats has to do it at some point...[[Special:Contributions/108.162.216.8|108.162.216.8]]<br />
:Sure, but that's surely not the worker's ''only'' task. No one will pay someone just to peel lint. [[User:NealCruco|NealCruco]] ([[User talk:NealCruco|talk]]) 16:38, 24 March 2014 (UTC)<br />
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If you had enough lint to remove you may need to hire more than one person to do it. If I needed lint peeled I would pay a reasonable wage for someone to do it. [[Special:Contributions/108.162.246.117|108.162.246.117]] 18:46, 24 March 2014 (UTC)<br />
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Do you think Randall would draw some cartoon just to mess with the people here at explainxkcd? I know I would! [[User:Bigfatbernie|Bigfatbernie]] ([[User talk:Bigfatbernie|talk]]) 19:01, 24 March 2014 (UTC) ([[User talk:bigfatbernie|talk]])<br />
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biting into soft wax could also be stated as 'leaving an impression'<br />
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:I can see why peeling lint is fun (at least for 5 minutes) as it's soft and it feels good and you can play around with it and its a rather relaxing task. The light saber stuff obviously is fun, too. But I really don't see why anyone would want to bite into a lump of slightly soft wax. Does anyone do that in real life? Sounds pretty disgusting to me. -- [[Special:Contributions/173.245.53.137|173.245.53.137]] 19:53, 24 March 2014 (UTC)</div>173.245.53.137https://www.explainxkcd.com/wiki/index.php?title=1334:_Second&diff=611171334: Second2014-02-26T14:01:25Z<p>173.245.53.137: /* Explanation */ Web -> Webring (probably just a typo)</p>
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<div>{{comic<br />
| number = 1334<br />
| date = February 24, 2014<br />
| title = Second<br />
| image = second.png<br />
| titletext = Let me just scroll down and check behind that rock. Annnnd ... nope, page copyright year starts with '19'. Oh God, is this a WEBRING?<br />
}}<br />
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==Explanation==<br />
{{w|Google}} is a popular search engine. Google's searching algorithms are widely regarded as the most accurate and useful. If your search terms were sufficiently detailed, you will be able to find what you were looking for on the first page. Having to view the second page indicates your search terms were too vague or the answer to your query doesn't exist. Especially when the search results are more than thousands or more items, only the very first results are mapping to the real idea of the user. The second page is not helpful for the issue.<br />
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[[Cueball]], after failing to find his query in the first page of results, takes a curious peek at the second page. This is represented by a not-at-all subtle metaphor in which Cueball is about to wander into a sun-baked desert. According to the title text, he finds one vaguely relevant webpage, but it's over {{#expr:{{CURRENTYEAR}}-2000}} years old.<br />
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The title text refers to {{w|webring}}s. Webrings consist of multiple websites that are connected together, usually with a common theme. They connect from one website to the next, eventually leading back to the starting site. They were popular in the 1990's as a popular way of boosting your search ranking, but newer algorithms in Google and other search engines are now detecting and penalizing web sites for such tactics.<br />
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==Transcript==<br />
:[Cueball in a desert standing before a rock.]<br />
:Rock: Greetings, stranger.<br />
:Rock: Whatever quest drives you, '''''abandon it.'''''<br />
:Rock: You shall find no answers in these desolate wastes.<br />
:Cueball: I knew I wouldn't.<br />
:Cueball: I guess I... just had to see.<br />
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:I hate feeling desperate enough to visit the second page of Google results.<br />
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{{comic discussion}}<br />
[[Category:Comics featuring Cueball]]<br />
[[Category:Internet]]</div>173.245.53.137https://www.explainxkcd.com/wiki/index.php?title=499:_Scantron&diff=59631499: Scantron2014-02-08T22:13:40Z<p>173.245.53.137: /* Explanation */ As a German, I never came across this sentence during my school life ;)</p>
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<div>{{comic<br />
| number = 499<br />
| date = November 3, 2008<br />
| title = Scantron<br />
| image = scantron.png<br />
| titletext = Also, after all the warnings about filling in the bubbles completely, I spent like 30 seconds on each one.<br />
}}<br />
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==Explanation==<br />
This comic is a take on the instructions "Remember to use a #2 pencil on the Scantron" that most modern students in the USA have heard something approaching a hundred times. {{w|Scantron}}s are standardized {{w|Machine-readable data|machine-readable papers}} used by students to answer multiple-choice tests. Often, the instructor will remind students to use a #2 pencil, which is the US term for the {{w|pencil hardness}} HB. HB pencils use a medium-hardness graphite considered ideal for Scantron use because the graphite is soft enough to leave a dark mark but hard enough to not smudge, both aspects that improve the performance of machine-readable paper.<br />
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The joke is that the student used a #3 pencil, which has a slightly harder graphite rating, on the Scantron as opposed to a #2 pencil, causing the grading machine to explode and harm some characters off-panel.<br />
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The title text refers to the instruction to "fill in all the bubbles completely." This again improves the performance of machine-readable paper. [[Randall]] states that he spent an inordinate amount of time making sure his markings were perfect because he had been warned so many times to do so (five seconds is usually enough).<br />
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==Transcript==<br />
:[A classroom scene. There are two desks, and the front one is occupied by the student. Miss Lenhart stands panel right facing the student.]<br />
:Miss Lenhart: Okay class, I've turned in your exams for grading. Now—<br />
:Student: Miss Lenhart?<br />
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:[View is now simply student in desk and teacher. Teacher looks horrified.]<br />
:Student: I used a #3 pencil instead of a #2. Will that mess anything up?<br />
:Miss Lenhart: You '''WHAT?'''<br />
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:[Teacher stands, covering her head, in front of an off-panel right explosion. The unseen speaker is off-panel right.]<br />
:''AIEEE''<br />
:'''''BLAM'''''<br />
:Unseen speaker: OH GOD!<br />
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:[The student and teacher are left-panel, both looking shocked. The unseen speaker is still off-panel right.]<br />
:Unseen speaker: OH GOD! I've never seen so much blood!<br />
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{{comic discussion}}<br />
[[Category:Comics featuring Miss Lenhart]]</div>173.245.53.137https://www.explainxkcd.com/wiki/index.php?title=Talk:1305:_Undocumented_Feature&diff=55429Talk:1305: Undocumented Feature2013-12-18T08:06:02Z<p>173.245.53.137: </p>
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<div>This sound pretty cool... Anyone know if it's real or which tool it's in? [[Special:Contributions/173.245.55.222|173.245.55.222]] 05:53, 18 December 2013 (UTC)<br />
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its real, there are 8 other users, but must stay a secret.<br />
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Okay, let's be honest: how many of us, upon seeing today's comic, immediately went here to see if it was real or not? --[[Special:Contributions/108.162.245.4|108.162.245.4]] 07:47, 18 December 2013 (UTC)<br />
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I honestly did just that. --[[Special:Contributions/173.245.53.137|173.245.53.137]] 08:06, 18 December 2013 (UTC)</div>173.245.53.137