Difference between revisions of "Talk:2892: Banana Prices"

Explain xkcd: It's 'cause you're dumb.
Jump to: navigation, search
(not statistical sins)
Line 26: Line 26:
 
The explanation is needlessly long and on occasion wrong. Some one tried to fix it by adding paragraphs in parentheses. If something is confusingly written or wrong it's generally best to rewrite instead of adding a paragraph.
 
The explanation is needlessly long and on occasion wrong. Some one tried to fix it by adding paragraphs in parentheses. If something is confusingly written or wrong it's generally best to rewrite instead of adding a paragraph.
 
In my eyes the comic is Randall's comment on the fact that agricultural products have become relatively cheaper by having price increases below the inflation rate. This is a long sgandingytrend since the beginning of industrialization and the only reason we can afford new other things than food. --[[Special:Contributions/172.71.160.24|172.71.160.24]] 07:56, 10 February 2024 (UTC)
 
In my eyes the comic is Randall's comment on the fact that agricultural products have become relatively cheaper by having price increases below the inflation rate. This is a long sgandingytrend since the beginning of industrialization and the only reason we can afford new other things than food. --[[Special:Contributions/172.71.160.24|172.71.160.24]] 07:56, 10 February 2024 (UTC)
 +
 +
Are these really 'statistical sins'?
 +
 +
Hot take but I agree with comments that it's reading too much into this comic to call it "a meta-joke about lying with data". Here are the supposed "sins" listed:
 +
 +
# false precision
 +
# extrapolating an order of magnitude deeper into the future than is advisable
 +
# assuming that a non-exponential quantity - prices - will grow exponentially
 +
# referring to a logarithmic extrapolation as linear
 +
# ignoring historical norms and high variability in making future predictions
 +
# articulating multiple potential scenarios that are actually highly correlated with each other.
 +
 +
Taking them one by one:
 +
 +
> 1. false precision
 +
 +
Projecting prices hundreds of years into the future is farcical, for sure, but I'm not sure that's "false precision". "False precision" would be saying "on January 6 2254 this joke will finally be stale". But the comic gives a very imprecise (and wrong!) range "another century or so". If anything the precision of the projection is downplayed.
 +
 +
> 2. extrapolating an order of magnitude deeper into the future than is advisable
 +
 +
This one is true, and is the source of the humor.
 +
 +
> 3. assuming that a non-exponential quantity - prices - will grow exponentially
 +
 +
Inflation _is_ an exponential process, _by design_. Monetary policy holds the explicit aim--more or less upheld since the 1980s--to keep long-range inflation within a low and positive percentage around the 2% mark. That is the aim. There are periods of higher (and lower!) inflation but overall, the Fed has been successful at keeping inflation within the target range for the last 40 years or so that this has been the dominant monetary policy paradigm. And growth on a constant percentage rate in a series just _is_ exponential growth; that's what exponential means.
 +
 +
> 4. referring to a logarithmic extrapolation as linear
 +
 +
idk maybe. The graph is on a log scale but a log scale has the quality of allowing us to visualize an exponential trend on a straight (linear) line. That's the beauty of it. I don't think there's a "sin" here.
 +
 +
> 5. ignoring historical norms and high variability in making future predictions
 +
 +
What historical norms are being ignored here exactly? Long-run inflation is fairly stable.
 +
 +
> 6. articulating multiple potential scenarios that are actually highly correlated with each other.
 +
 +
idk can anyone find a quote from the statistical Bible to support the idea this is a sin? Obviously there are problems. But to my mind, showing that multiple models converge on an approximate answer is a very good way to test convergent validity of a prediction.
 +
 +
So maybe 1 or 2 of the sins alleged are real, imo. [[User:NZUlysses|NZUlysses]] ([[User talk:NZUlysses|talk]]) 17:22, 10 February 2024 (UTC)

Revision as of 17:22, 10 February 2024

Is it a linear extrapolation? Or does it only appear so because the Y axis is logarithmic? Inflation is logarithmic, since it's expressed in percentages. Barmar (talk) 17:04, 9 February 2024 (UTC)

Well, the lines of extrapolation are (invoked as) linear, by dint of the height above the baseline being preconverted to a logarithmic function of the represented axial value. Rather than taking exponential-style extrapolation of data and 'happening' to linearise it through the subsequent transformation, it is almost certainly going to have been merely establishing some trend point(s) through which such an exponential would pass and using that to directly guide the linear plot that (on the converted scale) is the functionally equivalent result to doing it with every point. 172.71.178.77 17:26, 9 February 2024 (UTC)

OK, so... my reading of the comic after studying it for a while is that Randall is making a sophisticated meta-joke about 'lying with data" and unreliable precision and how easy it is to be fooled. He knows, of course, that this graph's "prediction" is completely arbitrary and is likely to be VERY wrong. He is intentionally breaking a whole set of statistical best practices in this graph. If so, I think this comic is one of the most-layerd and subtle he's ever done. You have to know a lot about statistical best practices to see what he's really doing here. .. What's so interesting to me is him using the voice of the caption-writer -- usually good ol' reliable Randall -- to actually be the butt of the joke. ... If someone wants to claim that this is more sarcasm than "unreliable narrator," I guess that's a reasonable interpreation, but the use of the word "probably" in the caption makes me think we're supposed to take the caption-writer seriously. Laser813 (talk) 18:38, 9 February 2024 (UTC)

I don't know, I think meta-humor is typically reserved for the title text. I think the comic is a cheap gag about bananas and that the line will eventually become outdated, and and it's oversimplified so that the logic of his joke is clear. The caption is written in a similar speech style to the quote, and I think the title text is Randall's admission that the graph isn't the best. I don't think flaws in the graph are intentional as part of some humor on graph design, just a consequence of making the graph clear enough to not be distracting from the joke. Kittyabbygirl (talk) 21:04, 9 February 2024 (UTC)
I think the comic is about how obvious it is that wealthy people are influencing our societies, because they know nothing about our lives, and then kind of how you can comment on that without as much lashback if you criticize yourself as well. Or course, people are getting less and less skilled as we more and more do what we are told and influenced instead of what we would find on our own. 108.162.245.168 01:25, 10 February 2024 (UTC)

Bananas are a special case: Basically we have a monoculture. With no genetic variations, bananas are highly vulnerable to the emergence of specialized pathogens and currently Panama 4 is threatening the Cavendish banana: https://www.theguardian.com/food/ng-interactive/2022/apr/14/climate-crisis-food-systems-not-ready-biodiversity So trying to fit this question of "will it go extinct soon?" into a smooth inflation price increase might be another butt of the joke

172.71.246.88 18:49, 9 February 2024 (UTC)

Randall is way off-base here, by about an order of magnitude. The episode is about Bluth frozen bananas, which require refrigeration, chocolate, and custom labor; they also do not have the economies of scale of fresh bananas. The AD wiki says the prices are >$1; in "Top Banana," Maeby says they cost at least $1. In real life, frozen bananas cost $5 in LA, $8 at ice cream shops on LA-area beaches. This is a joke similar to the Pulp Fiction $5 milkshake; milkshakes have been much more expensive than that for years. --172.70.207.149 19:12, 9 February 2024 (UTC)

Randall sometimes ignores basic elements about how the real world works in order to make a nerdy joke or point. The comic last week about Black Hat being tracked 8,000 miles away by NIST is a good example of that. The whole thing rests on us entering into his (slightly) alternate universe with him. Laser813 (talk) 20:37, 9 February 2024 (UTC)

I am tempted to say "Keep the change." "What from a fiver." "Yes the world is going to end." At the time of the radio series, it would have been an excessive amount of change to give away. They did not keep it for the film, when a fiver would barely pay for one of the six beers. 172.69.195.23 19:38, 9 February 2024 (UTC)

Using log scale here is not a joke. It's perfectly legit. Constant inflation is actually an exponential relation. For example, if prices go 10% up every year, in two years they won't be 20% higher but 21% because 1.10*1.10=1.21. And such an exponential relation becomes linear when plotted using a logarithmic y axis.--Pere prlpz (talk) 21:57, 9 February 2024 (UTC)

With 34 Trillion debt I would not expect a US dollar to be worth a tenth of a banana in a time frame of hundreds of years - How far they can kick the can is unknown but I would guess years or at best decades over centuries. "what can not be paid back will not be paid back" A banana is worth a banana - it is the money that is losing value and to sustain this circus that must accelerate. 108.162.241.216 22:33, 9 February 2024 (UTC)

As Pere points out, the logarithmic scale is in fact the correct scale for estimating the uncorrected price of an item, such as a banana. 172.71.103.214 22:40, 9 February 2024 (UTC)

The explanation is needlessly long and on occasion wrong. Some one tried to fix it by adding paragraphs in parentheses. If something is confusingly written or wrong it's generally best to rewrite instead of adding a paragraph. In my eyes the comic is Randall's comment on the fact that agricultural products have become relatively cheaper by having price increases below the inflation rate. This is a long sgandingytrend since the beginning of industrialization and the only reason we can afford new other things than food. --172.71.160.24 07:56, 10 February 2024 (UTC)

Are these really 'statistical sins'?

Hot take but I agree with comments that it's reading too much into this comic to call it "a meta-joke about lying with data". Here are the supposed "sins" listed:

  1. false precision
  2. extrapolating an order of magnitude deeper into the future than is advisable
  3. assuming that a non-exponential quantity - prices - will grow exponentially
  4. referring to a logarithmic extrapolation as linear
  5. ignoring historical norms and high variability in making future predictions
  6. articulating multiple potential scenarios that are actually highly correlated with each other.

Taking them one by one:

> 1. false precision

Projecting prices hundreds of years into the future is farcical, for sure, but I'm not sure that's "false precision". "False precision" would be saying "on January 6 2254 this joke will finally be stale". But the comic gives a very imprecise (and wrong!) range "another century or so". If anything the precision of the projection is downplayed.

> 2. extrapolating an order of magnitude deeper into the future than is advisable

This one is true, and is the source of the humor.

> 3. assuming that a non-exponential quantity - prices - will grow exponentially

Inflation _is_ an exponential process, _by design_. Monetary policy holds the explicit aim--more or less upheld since the 1980s--to keep long-range inflation within a low and positive percentage around the 2% mark. That is the aim. There are periods of higher (and lower!) inflation but overall, the Fed has been successful at keeping inflation within the target range for the last 40 years or so that this has been the dominant monetary policy paradigm. And growth on a constant percentage rate in a series just _is_ exponential growth; that's what exponential means.

> 4. referring to a logarithmic extrapolation as linear

idk maybe. The graph is on a log scale but a log scale has the quality of allowing us to visualize an exponential trend on a straight (linear) line. That's the beauty of it. I don't think there's a "sin" here.

> 5. ignoring historical norms and high variability in making future predictions

What historical norms are being ignored here exactly? Long-run inflation is fairly stable.

> 6. articulating multiple potential scenarios that are actually highly correlated with each other.

idk can anyone find a quote from the statistical Bible to support the idea this is a sin? Obviously there are problems. But to my mind, showing that multiple models converge on an approximate answer is a very good way to test convergent validity of a prediction.

So maybe 1 or 2 of the sins alleged are real, imo. NZUlysses (talk) 17:22, 10 February 2024 (UTC)