https://www.explainxkcd.com/wiki/api.php?action=feedcontributions&user=172.70.91.50&feedformat=atomexplain xkcd - User contributions [en]2024-03-28T22:14:39ZUser contributionsMediaWiki 1.30.0https://www.explainxkcd.com/wiki/index.php?title=Talk:2539:_Flinch&diff=220552Talk:2539: Flinch2021-11-09T10:05:52Z<p>172.70.91.50: </p>
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A follow-up joke: "Psychologist: I don't trust you not to give it a push."<br />
[[User:Who, me?|Who, me?]] ([[User talk:Who, me?|talk]]) 02:13, 9 November 2021 (UTC)<br />
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A sudden wind guest wouldn't add much momentum to a smooth, small object like a bowling ball in one swing. Even given minimal friction losses (air resistance and the chain's internal friction) I very much doubt it would speed it up enough to cause much of an impact. Also, unless Cueball has very bad luck or precognitive powers, he's unlikely to have set up the experiment perfectly in line with the next unexpected gust of wind, meaning any velocity vector change is likely to make the bowling ball miss the target scientist or engineer, not hit harder. [[User:Nitpicking|Nitpicking]] ([[User talk:Nitpicking|talk]]) 04:26, 9 November 2021 (UTC)<br />
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I disagree with the explanation's contention that the way Cueball is holding the ball means the experiment is being performed incorrectly. I think it's pretty clear he's not saying it will be released from exactly where he's holding it, since it's obviously not in front of any of their faces, and it's not yet above the mark on the floor. [[User:Esogalt|Esogalt]] ([[User talk:Esogalt|talk]]) 07:44, 9 November 2021 (UTC)<br />
:Ditto. Although I have in mind a way in which a (passive) string support could be arranged so that upon the outward swing it unwraps a ting little bit and returns upon a marginally lower/significantly more face-ward back swing (same K+P energy totals at all points), even starting with a taught string. Or of course an active support that moves on command, but that'd be definite cheating-with-intent as opposed to an 'accident'.<br />
:(I also imagine Randall saw the original, if not the Youtube parody, of your US Science-Explaining-Guy doing this for real. The Youtube parody had a cartoony 'face smash' edited in as the result as a (faux-?) bite back at the scientific rationalism. If I could remember the guy's name I'd have looked for video links to potentially insert, but all I'm getting is the likes of Brian Cox doing it (successfully), on a quick and broad search.) [[Special:Contributions/172.70.91.50|172.70.91.50]] 10:05, 9 November 2021 (UTC)</div>172.70.91.50https://www.explainxkcd.com/wiki/index.php?title=2538:_Snack&diff=2203882538: Snack2021-11-05T20:42:53Z<p>172.70.91.50: </p>
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<div>{{comic<br />
| number = 2538<br />
| date = November 5, 2021<br />
| title = Snack<br />
| image = snack.png<br />
| titletext = Although grad students, suddenly reminded that food exists, tend to just grab and devour both without further discussion.<br />
}}<br />
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==Explanation==<br />
{{incomplete|Created by an APPLE COOKIE - Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br />
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Psychologists have a great interest in the study of altruism, and whether it truly exists. Undergraduate psychology students therefore, having spent too much time studying rather than interacting with people, might start to believe that when they are shown altruism, they are unknowing participants in a psychological study. Therefore, Randall proposes that if you want to freak out a psychology student, then you should behave altruistically towards them.<br />
The title text jokes that graduate students have so much work to do, they don't ponder the implications of altruism, but rather devour the food and return to their work.<br />
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==Transcript==<br />
{{incomplete transcript|Do NOT delete this tag too soon.}}<br />
: Ponytail: Hey, do you want a cookie? Or an apple?<br />
: Cueball: Who are you!? Did the IRB approve this!? Is everyone here an actor!?<br />
: [Caption under the panel:]<br />
: The best prank you can play on Psychology students is just to offer them a snack.<br />
{{comic discussion}}</div>172.70.91.50https://www.explainxkcd.com/wiki/index.php?title=2537:_Painbow_Award&diff=2203042537: Painbow Award2021-11-04T01:55:35Z<p>172.70.91.50: /* Explanation */ Miskeyed</p>
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<div>{{comic<br />
| number = 2537<br />
| date = November 3, 2021<br />
| title = Painbow Award<br />
| image = painbow_award.png<br />
| titletext = This year, our team took home the dark blue ribbon, better than the midnight blue we got last year but still short of the winning navy blue.<br />
}}<br />
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==Explanation==<br />
{{incomplete|Created by MELLLVAR - Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br />
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This comic makes fun of the sometimes-displeasing color gradients used in the figures for scientific papers by suggesting that the scientists picking them are in competition to use the least-pleasing gradient. The title of the comic is a portmanteau of "pain" and "rainbow" suggesting a humorous name for terrible gradients.<br />
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The gradient here showcases a collection of unintuitive and unhelpful decisions. Starting from the top, white fades down into green, which then fades into red (passing through brown in the middle instead of yellow, indicating {{w|subtractive color}} mixing instead of {{w|additive color}} mixing, for no obvious reason). The red then turns ''back'' into green as the intensity increases further. Red and green in close proximity make the power levels hard or impossible to distinguish for those with {{w|Color_blindness#Protanopia|protanopic colorblindness}}. This confusion is repeated at lower power levels, where blue transitions to black and then back again, before finally transitioning back into white. The highest and lowest recorded power levels have the same color value, which is less than ideal.<br />
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Although it's possible (for someone with full color vision) to interpret data from this graph from context clues - the white that fades to green is high-energy white, while the white that fades to blue is low-energy white - there's no benefit to doing things this way, and a lot of downsides.<br />
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Real-world analogues to the Painbow Award include radar meteorology charts, where different types of precipitation have different color schemes that can overlap and blend in confusing transition zones.<br />
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The title text takes the concept of bad color combinations further, suggesting the use of navy blue, dark blue, and midnight blue for first, second, and third respectively, even though most people would perceive these as being the same or very similar colors. However, the choice of blue(s) may be a direct play upon the association of the {{w|Blue Riband}} (a.k.a. "Blue Ribbon") and/or {{w|Le Cordon Bleu|Cordon Bleu}} (likewise, but this time direct from the French) awards, extended in common use for excellence across a much wider range of competitive fields.<br />
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For rosette-rewarded competitions (e.g. livestock parades, dog-shows, etc) the first prize ones are commonly blue (red and yellow for 2<sup>nd</sup> and 3<sup>rd</sup>, respectively), though it may not be logically obvious to someone unfamiliar with this, perhaps more used to yellow depicting the 'gold standard, first place' indicator or red as the most alerting hue in some other ranking situations. Where a depicted award schema ''is'' directly gold/silver/bronze-influenced, however, the gold and bronze 'metallic off-yellows' can sometimes be more confused with each other than with the mid-level desaturated 'silver'<br />
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==Trivia==<br />
* When originally uploaded, the caption used the phrase "color gradient" rather than "color scale"<br />
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==Transcript==<br />
{{incomplete transcript|Do NOT delete this tag too soon.}}<br />
:[A graph named 'Figure 2' with two axes is shown. The vertical axis is labeled 'λ' and the horizontal axis is labeled 'θ (phase)'. On the right side, a bar labeled 'Peak Energy' is shown, with colors starting from black, to green, to red, to green, to yellow, and to white from bottom to top. The center of the graph is a messy shape with ugly gradients from these colors.]<br />
:Caption under the panel: Every year, disgruntled scientists compete for the Painbow Award for worst color scale.<br />
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{{comic discussion}}<br />
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[[Category:Comics with color]]</div>172.70.91.50https://www.explainxkcd.com/wiki/index.php?title=Talk:2533:_Slope_Hypothesis_Testing&diff=219880Talk:2533: Slope Hypothesis Testing2021-10-27T15:19:04Z<p>172.70.91.50: </p>
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In the line "Randall has repeatedly made comics about this hopeful error", should specific examples be provided? I know /882 is one, but I'm blanking on any others. [[Special:Contributions/172.68.132.114|172.68.132.114]] 10:21, 26 October 2021 (UTC)<br />
:Definitely, otherwise it would not be very useful. --[[Special:Contributions/162.158.203.54|162.158.203.54]] 13:10, 26 October 2021 (UTC)<br />
:hi, I added the line. <thinking-out-loud removed in copyediting>. I think there was one where article titles that blatantly used poor statistical techniques were listed, not sure. [[Special:Contributions/172.70.114.3|172.70.114.3]] 14:40, 26 October 2021 (UTC)<br />
I love it. [[User:Fwacer|Fwacer]] ([[User talk:Fwacer|talk]]) 02:52, 26 October 2021 (UTC)<br />
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I imagine that the problem here is that the errors are not independent. I can't find anything else wrong with this, but I feel like there's something obvious I'm not seeing. They might revoke my statistics degree if I miss something big here, hehe.--[[User:Troy0|Troy0]] ([[User talk:Troy0|talk]]) 03:06, 26 October 2021 (UTC)<br />
:The scores are clearly the one score they originally (sometime prior to the expanded test) received. Either that or multiple tests with the same exam questions without having given them enough feedback to change their answer-scheme at all. The volumes are probably a "good go at screaming" on demand, belying any obvious "test result -> thus intensity of scream" (what might be expected if the scream(s) of shock/joy/frustration were recorded immediately upon hearing a score).<br />
:What they have here is a 1D distribution of scream-ability/tendency (which was originally a single datum), arbitrarily set against test scores. (Could as easily have been against shoe-size, father's income-before-tax, a single dice-roll, etc.)<br />
::I initially assumed that the participants are screaming in response to learning their scores, so the relationship is not arbitrary -- the students with good scores sceam loudly with joy. [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 14:45, 26 October 2021 (UTC)<br />
:::Perhaps it was that (except the screaming volume is clearly confounded by other factors, such as how loudly they normally scream) but asking them to "scream again" seems to show far more personal correlation than emotional attachment, for they are the same people but time has passed to reduce the spontenity of the response and their newer submissions are ''at best'' "try to scream like you did when you heard your score the first time". Which is problematic and not really a valid new response to add to the list. At best, it's a test of replay consistency (now unlinked from the original feeling). [[Special:Contributions/172.70.85.185|172.70.85.185]] 15:57, 26 October 2021 (UTC)<br />
:Whether there ''was'' an original theory that grades correlated with intensity of vocalisation is perhaps a valid speculation, but clearly the design of the test is wrong. Too few datum points, in the first instance, and the wrong way to increase them when they find out their original failing.<br />
: The true solution is to recruit more subject. (And justify properly if it's intensity of spontaneous result-prompted evocations or merely general ability to be loud that is the quality the wish to measure. Either could be valid, but it's not obvious that the latter is indeed the one that they meant to measure.) [[Special:Contributions/141.101.77.54|141.101.77.54]] 04:21, 26 October 2021 (UTC)<br />
: It's pretty straightforward. This is a simple linear regression, Y = α + βX + ε, where α and β are parameters and ε is a random variable (the error term). Their point estimations for α and β are correct. But their confidence intervals (and thus p-values) are wrong, because they are based on a false assumption. They constructed their intervals assuming ε was normally distributed, which it clearly is not. ε will always be approximately normally distributed if the central limit theorem applies, but it does not apply here. The central limit theorem requires that the samples be independent and identically distributed. Here, they are identically distributed, but they are not remotely independent. After all, the same people were selected over and over again. Therefore ε will probably not be randomly distributed (it isn't even close), and the confidence intervals (and so p-values) are wrong. [[Special:Contributions/172.70.178.47|172.70.178.47]] 09:10, 26 October 2021 (UTC)<br />
:: You seem to be the only person so far who's learned in academia why this is wrong. Is the current state of the article correct? [[Special:Contributions/172.70.114.3|172.70.114.3]] 14:31, 26 October 2021 (UTC)<br />
: The scientific error isn't quite what people are saying it is. The issue here is not "reusing a single test score" or an issue with non-normality of errors, the issue is that the data are *nested* within participants and that isn't being accounted for. There are fairly standard ways of managing this, at least in the social science literature (and these ways are statistically valid), most commonly the use of multilevel modeling (also known as hierarchical linear modeling). This accounts for the correlated nature of the errors. Now, even using the right method they're not going to attain statistical significance, but at least they aren't making a statistical mistake.<br />
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I don't think the title text speakers are unidentified, I'm pretty sure it's a direct continuation of the dialogue in the last panel. [[User:Esogalt|Esogalt]] ([[User talk:Esogalt|talk]]) 04:11, 26 October 2021 (UTC)<br />
:I agree. the second speaker starts to say "I said, are you sure--", this is the start of Cueball's last line. I think this is intended to be Cueball and Megan trying to talk about the results while the students are still screaming. [[User:TomW1605|TomW1605]] ([[User talk:TomW1605|talk]]) 06:45, 26 October 2021 (UTC)<br />
::It could also be the case that their hypothesis was true and they failed so badly at statistics, that their voices are inaudible now.<br />
:::Because, since they didn't write that test, their score is zero. [[Special:Contributions/108.162.241.143|108.162.241.143]] 14:29, 26 October 2021 (UTC)<br />
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Is there a polynomial that better fits this data? [[Special:Contributions/108.162.241.143|108.162.241.143]] 14:29, 26 October 2021 (UTC)<br />
:Given three points, there's a ''circle'' that exactly fits them... ;) [[Special:Contributions/172.70.85.185|172.70.85.185]] 15:57, 26 October 2021 (UTC)<br />
:Also, infinite number of polynomials which fits this data exactly. -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 23:06, 26 October 2021 (UTC)<br />
::But ''exactly one'' circle (assuming all mutually different, and not already upon a line), in an {{w|Circumscribed_circle#Triangles|elegantly obvious}} manner. Therefore clearly the more individually significant statistical match for three datum points. :P [[Special:Contributions/172.70.162.173|172.70.162.173]] 11:50, 27 October 2021 (UTC)<br />
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Speaking as the person who wrote the explanation for "slope hypothesis testing," we need someone to write a better explanation for it. It's just a placeholder meant to patch a gap until someone who knows what they're talking about (or what to google) can write a better one. [[User:GreatWyrmGold|GreatWyrmGold]] ([[User talk:GreatWyrmGold|talk]]) 14:30, 27 October 2021 (UTC)<br />
:My (armchair) summary(!) would be that a general proposition is that there is a simple linear relationship between two factors (or their logs/powers/whatevers, reformulated as necessary) so those are plotted and their conformity to a gradient(±offset) is evaluated.<br />
:The slope is defined by just two values which can, if necessary*, be emperically tested against the 'wrongness' of the points against the line (including error allowances) to find that line which is itself therefore minimally 'wrong', and that remaining wrongness (including how much of the possible error may need to be accepted) conveys the conformity or otherwise and you have also tied down the possibly unknown relationships - as best you are allowed to.<br />
: * - though there are doubtless many different direct calculation/reformulation methods that don't require progressive iterations towards a better solution. And identify where multiple minima might lie in the numeric landscape.<br />
: (Summary, indeed! This is why I didn't myself feel the need to try to do anything with the Explanation. It just seems like a typical Munrovian mash up of {{w|Statistical Hypothesis Testing}} and working with a slope. If I was ever taught this Slope-specific one (other than assessment by inspection, to preface or afterwards sanity-check loads of Sigma-based mathematics/etc that one can easily mess up by hand, or GIGO when plugged into a computer wrongly) then I've forgotten its name.) [[Special:Contributions/172.70.91.50|172.70.91.50]] 15:19, 27 October 2021 (UTC)</div>172.70.91.50