Editing Talk:2295: Garbage Math

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== Inclusion in Series ==

This is not a Covid19 comic. One could think that this is a comment on the difficulties of modeling the corona virus outbreak, but since discussions of exponential functions are only a small part in the comic I believe it is just a general comment on floating point arithmetic mixed in with statistical considerations. --[[Special:Contributions/108.162.229.242|108.162.229.242]] 17:28, 17 April 2020 (UTC) 
:I disagree that this is not a COVID-19 comic. I also believe the one about visualizing large numbers was COVID-19 related. On the other hand, I like the idea that Randall might produce exactly 19 comics related to SARS CoViD 2019, so I'm prepared to concede the point for the sake of arbitrary numerological appeal. 
:[[User:ProphetZarquon|ProphetZarquon]] ([[User talk:ProphetZarquon|talk]]) 18:42, 17 April 2020 (UTC)
::I think Exa-Exabyte was a real stretch (the virus doesn't even have DNA), but there is a tenuous link so whatever. The idea that ''this'' comic is related, on the other hand, stretches past the breaking point. There's hardly anything that can't be linked to global events if we try hard enough, but that doesn't mean there's an actual link. Sometimes a comic about garbage math is just a comic about garbage math. [[Special:Contributions/172.69.71.58|172.69.71.58]] 19:33, 17 April 2020 (UTC)
:::I think this one's much more likely to be a coronavirus comic than Exa-Exabyte was. There's an awful lot of COVID data, much of it either very imprecise or outright garbage; and the comic directly before this one ([[2294]]) involved bad modeling of said COVID data, so clearly COVID data (and its limitations) is something Randall's currently thinking of and drawing comics about. [[User:Pelosujamo|Pelosujamo]] ([[User talk:Pelosujamo|talk]]) 20:25, 17 April 2020 (UTC)
::::Exa-Exabyte was centered around biology, which gives reason to believe it was covid19 related. This one seems much more uncertain. Any conclusion that it is related is based on garbage. Jokes aside, It seems like much more of a stretch to me. Randall thinking in those terms is a reasonable argument, but personally I am going to assume this is the chain breaker unless a direct reference is made in the next couple comics since ending at 19 is would be appropriate. [[Special:Contributions/172.69.70.209|172.69.70.209]]
:: While this comic has no ''direct'' reference to Covid-19 it does appear that the math might be related. At this point we can't know if the series has ended.  As such I've edited the paragraph in the explanation to identify the known ambiguities. And now I realize I've made an explanatory paragraph about "knowledge error bars"  in the explanation of a comic about numerical error bars.[[User:Iggynelix|Iggynelix]] ([[User talk:Iggynelix|talk]]) 14:42, 18 April 2020 (UTC)
:::No. The reason it appears the math might be related is ''because the math relates to everything, everywhere''. That's not enough of a connection. During this pandemic, there will be a lot of comics related to the coronavirus, many of them in a row, but that doesn't mean that every comic that could be tangentially related if you squint just right should qualify as a COVID-19 comic (I ''still'' think Exa-Exabyte doesn't). There needs to be a real link, because just about ''anything'' could be twisted into a relation if you try hard enough. As a test, I hit [[Special:Random]] and got [[346: Diet Coke+Mentos]]. Wouldn't you know, that's a coronavirus comic! The father, you see, actually had COVID-19 and died, but Diet Coke and Mentos has brought him back! No. The line should be drawn here. The streak has ended. [[Special:Contributions/172.69.68.197|172.69.68.197]] 17:02, 18 April 2020 (UTC)

:::::I am pretty sure this IS related. Right now, everybody and his grandmother is staring at the Johns Hopkins Coronavirus numbers for different countries. Entire newspaper articles are written about these numbers and about why one country is apparently faring better than the other and what this means. The numbers are made into fancy graphics.  People use these numbers to calculate fatality rates and cure rates. Politicians might even use these numbers to make decisions.
:::::And all this even though everybody KNOWS that the numbers cannot really be compared from one country to the other, because testing prerequisites vary, testing availability varies, testing procedures vary, criteria used to include a death as a coronavirus death vary. The sources of the numbers are very different and might not always be reliable. [Apparently, they include local language newspapers, website and even social media accounts. How many people DOES the Johns Hopkins University have to track all these sources reliably, worldwide, in local languages?] And not to forget some countries probably are downright lying.
:::::And still, people are comparing. I've read articles where the author admits the numbers are probably garbage in one sentence and then STILL goes on to calculate fatality rates from them in the next sentence. So, most PROBABLY related. 

::::::I challenge you to find a comic in the archive that can't be twisted to say it's related to COVID-19. At this point people are finding connections in the same way that people analyze "the curtain is blue". [[Special:Contributions/108.162.245.26|108.162.245.26]] 22:06, 19 April 2020 (UTC)
--[[Special:Contributions/141.101.69.153|141.101.69.153]] 21:53, 19 April 2020 (UTC)
:::::::Don't you mean the dress is blue?
:::::::I think this is more SARS-CoV-2 related than exa-exa (or Conway), but the desire is for there to have been 19 in a row, so there were 19 in a row. No doubt the next strip will be seen as the first in a second run of 19 [[Special:Contributions/162.158.34.222|162.158.34.222]] 23:33, 23 April 2020 (UTC)


This comic very much reminds me of this article: [https://www.realclearmarkets.com/articles/2020/04/17/its_decidedly_not_the_math_its_always_people_489344.html 
It's Decidedly Not the Math. It's Always People] So much so that my first thought was that the comic was inspired by it, though of course I can't prove it.[[User:BrianZ|BrianZ]] ([[User talk:BrianZ|talk]]) 00:52, 20 April 2020 (UTC)


== Math and Error bars ==

Well this is surprising came here thinking I understood it just to see what the discussion looked like. Ended up learning something new. I was able to understand intuitively the comic. But this is my first exposure to actually doing math on the error bars. I think I was supposed to do that in college but I don't remember anyone ever explaining how it should work. --[[Special:Contributions/162.158.63.208|162.158.63.208]] 18:14, 17 April 2020 (UTC)

In recent days, there have been a number of math "quizzes" in this same type of format, albeit generally with only addition and maybe multiplication, appearing on Facebook.  Should the explanation include a reference to this as a possible contributing reason for Randall's comic?  One could also argue that those quizzes have been appearing on Facebook as a way to spend/waste time during the coronavirus pandemic lock-down, making he comic at least tangentially related to Covid19 LIES.
:: Unsigned vandalism? /\  [https://www.explainxkcd.com/wiki/index.php?title=Talk:2295:_Garbage_Math&diff=190866&oldid=190856 change history] @user Please feel free to move your discussion to an appropriate forum and remove both the edit and this comment at such time. [[User:Iggynelix|Iggynelix]] ([[User talk:Iggynelix|talk]])

What's the difference between relative error and absolute error? I don't understand these terms. Maybe add?
: Absolute error is the amount of uncertainty in a value measured as a given number.  e.g. 5.7 &plusmn; 1.2 means that actual value lies somewhere between 5.7 - 1.2 and 5.7 + 1.2 = 4.5 to 6.9.  If you change the 5.7 to another value, you still get the same absolute difference of maximum and minimum values.  Relative error depends on the value you are comparing to.  e.g. 5.7 &plusmn; 10% would be between 5.7 - 0.57 and 5.7 + 0.57 = 5.13 to 6.27.  The absolute difference of maximum and minimum would change if the main number changes.  e.g. 11.3 &plusmn; 10% would be between 10.17 and 12.43, which has a greater absolute difference of maximum and minimum than the previous example. [[User:Nutster|Nutster]] ([[User talk:Nutster|talk]]) 01:54, 18 April 2020 (UTC)

Are all of these equations consistent with garbage = infinity?
: Unfortunately, as written, these equations would not make sense by defining Garbage as an infinity.  Infinity is not a number you can count to or measure in between integers.  Infinity is the idea of unending-ness.  Trying to use infinity as if it a finite number yields all sorts of invalid results.  In this case Garbage is defined as an arbitrary finite number with a large amount of uncertainty in its value. [[User:Nutster|Nutster]] ([[User talk:Nutster|talk]]) 01:40, 18 April 2020 (UTC)
::: That's a pretty good definition of 'garbage' in ''any'' case, plus or minus 10%. ( See also [https://www.weforum.org/agenda/2017/06/landfill-mining-recycling-eurelco/ valuable garbage]) [[User:Iggynelix|Iggynelix]] ([[User talk:Iggynelix|talk]]) 14:19, 18 April 2020 (UTC)

Would the summation divided by ''n'' just give you the arithmatic mean of the data set?  [[User:Nutster|Nutster]] ([[User talk:Nutster|talk]]) 01:55, 18 April 2020 (UTC)
:Pretty much, but the point is probably more that (without consistent bias across the set, just 'random' errors for each item) it suppresses the degree of garbagicity as outliers are increasingly nullified by the greater number of more competently accurate values and (if it's a symmetric error) opposing outliers. [[Special:Contributions/162.158.34.222|162.158.34.222]] 09:29, 18 April 2020 (UTC)

The statement that NaN^0 isn't fully justified and I'm not clear it belongs. [[User:Djbrasier|Djbrasier]] ([[User talk:Djbrasier|talk]]) 18:46, 18 April 2020 (UTC)
: I agree... It also isn't evident to me that this comic has anything to do with floating-point math, which is the only thing that could (even slimly) justify its inclusion. This is about statistics, not programming. --[[Special:Contributions/108.162.215.12|108.162.215.12]] 05:25, 19 April 2020 (UTC)

I'm concerned that, with "Precise Number" there's the usual confusion between Accuracy and Precision (''edit: and of course Resolution, too!''). A precise number can still be utter garbage, as 84.7489327(646475)% of all mathematicians could tell you. [[Special:Contributions/162.158.111.241|162.158.111.241]] 13:59, 19 April 2020 (UTC)
:The table of formulae for the propagation of variance &sigma; addresses that aspect. You can't know the accuracy of a result without knowing the precision of its calculation, and while reducing precision always reduces accuracy, it's not the other way around. But precision is inherent in the representation and operations, while accuracy is secondary when you aren't discussing the initial measurements of the inputs, so I think the terminology is correct.
:By the way, shout out to [https://www.explainxkcd.com/wiki/index.php?title=2295%3A_Garbage_Math&type=revision&diff=190882&oldid=190870 172.68.51.124] for filling out all but one of those table entries. I wonder where they looked them up. I'm guessing a ''CRC Handbook'' left over from High School chemistry or some such? Anyway, good job! This really looks classy now that it's been cleaned up a bit. [[Special:Contributions/162.158.255.64|162.158.255.64]] 06:45, 20 April 2020 (UTC)

Could someone please double check that the given uncertainty formula for "Precise number / ( Garbage – Garbage )" at the second to the bottom is correct? I'm not sure it properly accommodates the uncertainty of the numerator. [[Special:Contributions/162.158.255.64|162.158.255.64]] 07:48, 20 April 2020 (UTC)

Are the [https://www.explainxkcd.com/wiki/index.php?title=2295:_Garbage_Math&diff=191031&oldid=191030 changes from "=" to "≈"] correct? Either way, isn't the proper symbol for the relation "≅" ("approximately equal to") instead of "≈" ("almost equal to")? As is illustrated by catastrophic cancellation, an approximation may not be "almost" correct. But my question is, aren't those relations to the resulting standard deviation exact instead of approximate? [[Special:Contributions/172.69.22.152|172.69.22.152]] 04:16, 22 April 2020 (UTC)
:The formulas are the first approximation for small sigma. They are exact for a linear combination of the random variables in the term. With rising sigma, higher order terms can get relevant. Sebastian --[[Special:Contributions/172.69.54.141|172.69.54.141]] 07:46, 23 April 2020 (UTC)

Are the results truly correct? Wouldn't the final sum and product standard deviations be √2 10^6 ?

This comic makes me think about the "Garbage In, Garbage Out" rule of programming as well. Probably unrelated, but it just came to mind. [[User:Sarah the Pie(yes, the food)|Sarah the Pie(yes, the food)]] ([[User talk:Sarah the Pie(yes, the food)|talk]]) 11:14, 9 May 2021 (UTC)