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Old Yesterday, 08:47 AM   #441
Guybrush Threepwood
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Originally Posted by lobosrul5 View Post
If you flip a perfectly balanced coin 100 times and they all land as heads. The odds of it landing heads on the 101st time is still 50/50.
That is theoretically true, however the odds of 100 heads in a row is ~8 E-31, so if you ever saw it happen, your first, second and all subsequent thoughts should be that there is something fishy going on.
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Old Yesterday, 09:25 AM   #442
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Originally Posted by Guybrush Threepwood View Post
That is theoretically true, however the odds of 100 heads in a row is ~8 E-31, so if you ever saw it happen, your first, second and all subsequent thoughts should be that there is something fishy going on.
Indeed. If you saw a coin land heads up 100 times in a row, and were asked to bet on the next flip, you should obviously pick heads, because it's almost certain that the coin flip is NOT perfectly random (be it the coin itself, the flipping process, or both).
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Old Yesterday, 09:28 AM   #443
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Originally Posted by Ziggurat View Post
Indeed. If you saw a coin land heads up 100 times in a row, and were asked to bet on the next flip, you should obviously pick heads, because it's almost certain that the coin flip is NOT perfectly random (be it the coin itself, the flipping process, or both).
Hmm... If I saw someone flip 100 heads in a row, and then they asked me to bet on the next one, I'd say no thanks and walk away. I'm pretty sure that is the best answer.
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Old Yesterday, 09:35 AM   #444
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Originally Posted by Guybrush Threepwood View Post
Hmm... If I saw someone flip 100 heads in a row, and then they asked me to bet on the next one, I'd say no thanks and walk away. I'm pretty sure that is the best answer.
Indeed.
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Old Yesterday, 09:40 AM   #445
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Originally Posted by Guybrush Threepwood View Post
Hmm... If I saw someone flip 100 heads in a row, and then they asked me to bet on the next one, I'd say no thanks and walk away. I'm pretty sure that is the best answer.
Oh, indeed. Because its highly likely they are using some sort of sleight of hand trick and trying to take your money. I was just pointing out the "gambler's fallacy".
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Old Yesterday, 09:43 AM   #446
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Originally Posted by Guybrush Threepwood View Post
Hmm... If I saw someone flip 100 heads in a row, and then they asked me to bet on the next one, I'd say no thanks and walk away. I'm pretty sure that is the best answer.
That's a key bit of information, though: who are you betting against? If it's the guy flipping the coin, then yeah, that's a sucker's bet. If the bet is disconnected from whoever is flipping the coin, then go ahead and bet heads.
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Old Yesterday, 10:03 AM   #447
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Originally Posted by Cheetah View Post
NO!




Edit: I probably should have said:
The largest fully terrestrial animal native to Antarctica has the smallest genome of any terrestrial animal/insect/arthropod* so far sequenced.


*I'm not quite sure, definitely insect, arthropod as well I think. Maybe there are some parasites with small genomes.
Originally Posted by WhatRoughBeast View Post
You should keep in mind that the animals we think of in Antarctica, (penguins, mostly, and seals) are aquatic, not terrestrial.

There are a number of bird species which are found in Antarctica, but except for penguins they all head north for the winter, so are arguably not "native".
Ah. I see. Cool. (more likely quite frigid actually ... nyuk nyuk nyuk)
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Old Yesterday, 10:15 AM   #448
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Originally Posted by Ziggurat View Post
Indeed. If you saw a coin land heads up 100 times in a row, and were asked to bet on the next flip, you should obviously pick heads, because it's almost certain that the coin flip is NOT perfectly random (be it the coin itself, the flipping process, or both).
In practice, that's true enough. But in the more abstract, it's not.

The issue is that a string of heads is somehow "special". From a statistical point of view it's not.

Put it this way. Let's say you do, in fact, spend some idle time flipping a coin 100 times. Let's call the resulting sequence of heads and tails "RandomSequence". After you have done this, I provide you an unfalsifiable prediction of RandomSequence. Does this mean that the flip was somehow rigged? No. It means that either I was cheating (somehow) or that I got very lucky.

When we look at long strings of heads or tails, we think of them as somehow special, rather like my prediction of RandomSequence. In the long run, of course, they are (since they should not show up too often), but any predetermined sequence is equally special. As long as it is specified in advance. And any sequence which shows unlikely regularity is deemed to be special ex post facto.

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Old Yesterday, 11:18 AM   #449
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Originally Posted by WhatRoughBeast View Post
In practice, that's true enough. But in the more abstract, it's not.

The issue is that a string of heads is somehow "special". From a statistical point of view it's not.
It's only not special if the coin toss is random, and if you get 100 heads in a row, you should immediately suspect that it isn't.

If it's not random, then it can be special. For one thing, it's easier to fix a coin to come up heads 100 times in a row than it is to fix a coin to come up heads 50 times and tails 50 times but in a specific order. For another, if there's an actual person involved who can influence the outcome (ie, the flipper is cheating), then 100 heads in a row will BE special, and for two reasons. First, because humans perceive it to be special, and second, because we're bad at being random. If someone can control the outcome of the flips, then they are much more likely to flip it heads 100 times in a row than they are to flip it one specific but apparently random sequence.

ETA: but in line with your post, if you specify any sequence of 100 flips beforehand, and then get that sequence of 100 flips, you should also immediately suspect that it's not random. 100 heads is basically already specified by default.
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Last edited by Ziggurat; Yesterday at 11:21 AM.
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Old Yesterday, 11:34 AM   #450
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Because a coin toss is just practically random.

It's an easily accomplished task that can be done with a common item who's results or random enough for everyday purposes.

Coin tosses are perfectly deterministic, hobbyiest level engineers have already built coin flipping robots that can flip a coin to a desired outcome with fairly high accuracy by just controlling all the variables.

A "Coin Toss" is a fair approximation of "50/50 chance" on a practical level because the way we do it, just flipping the coin with our hands, in daily practice is impossible for us to control or observe all those variables.
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Old Yesterday, 12:07 PM   #451
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Originally Posted by Ziggurat View Post
That's a key bit of information, though: who are you betting against? If it's the guy flipping the coin, then yeah, that's a sucker's bet. If the bet is disconnected from whoever is flipping the coin, then go ahead and bet heads.
I'm having a hard time envisioning a scenario where it's not probably some sort of setup.
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Old Yesterday, 12:29 PM   #452
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Originally Posted by JoeMorgue View Post
just flipping the coin with our hands, in daily practice is impossible for us to control or observe all those variables.
Errrm no. Fixing the coin flip by hand is one of the first and easiest magicians tricks you can learn. Even with my fat sausage fingers, I can do it. Or at least I could back when I practiced.
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Old Yesterday, 12:54 PM   #453
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Originally Posted by Red Baron Farms View Post
Errrm no. Fixing the coin flip by hand is one of the first and easiest magicians tricks you can learn. Even with my fat sausage fingers, I can do it. Or at least I could back when I practiced.
My point is on a casual day to day level with neither purposely trying to screw with the results it's "sufficiently random for our purposes."
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Old Yesterday, 05:32 PM   #454
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Body mass of mammalian carnivores is limited to about a ton.

This paper was thrown into the face of the prehistoric predator matchup superfans to keep em quiet for a few years, until they found an even more enormous bear in Argentina.
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Old Yesterday, 06:04 PM   #455
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That’s interesting, but what stops them from evolving more robust bones? There will be diminishing returns but I’m not seeing a specific cutoff. I also don’t see what’s specific to mammalian predators here.
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Old Yesterday, 06:27 PM   #456
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Originally Posted by Venom View Post
Body mass of mammalian carnivores is limited to about a ton.
I'm uncomfortable calling that one a "fact." And not just in the pedantic way that all scientific facts are provisional, but even in the common parlance method. It's a plausible hypothesis, and what little I could see of the paper seemed to be reasonable, but I don't think I'd say it's a fact the way I would with "the force of gravity is proportional to 1/radius^2" or "the charge of an electron is opposite that of a proton" or even Cheetah's largest-antarctic-animal thing (which, in my mind, had an implied "that we know of")
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Old Yesterday, 06:55 PM   #457
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Originally Posted by Venom View Post
Body mass of mammalian carnivores is limited to about a ton.

This paper was thrown into the face of the prehistoric predator matchup superfans to keep em quiet for a few years, until they found an even more enormous bear in Argentina.
You forgot to specify terrestrial (the paper did specify). Take away that constraint, and you can get much bigger than 1 ton.
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Old Yesterday, 07:09 PM   #458
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Old Yesterday, 07:38 PM   #459
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Originally Posted by Ziggurat View Post
You forgot to specify terrestrial (the paper did specify). Take away that constraint, and you can get much bigger than 1 ton.
oo right, my mistake.

Last edited by Venom; Yesterday at 07:39 PM.
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Old Yesterday, 07:44 PM   #460
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Originally Posted by Roboramma View Post
Thatís interesting, but what stops them from evolving more robust bones? There will be diminishing returns but Iím not seeing a specific cutoff. I also donít see whatís specific to mammalian predators here.
As Zig pointed out I forgot to mention terrestrial mammalian predators.

Maybe differences in metabolism between mammals and non? The biggest bears aren't even close to medium-sized tyrannosaurids.

Just my pure guess.
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Old Yesterday, 08:32 PM   #461
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Originally Posted by Venom View Post
As Zig pointed out I forgot to mention terrestrial mammalian predators.

Maybe differences in metabolism between mammals and non? The biggest bears aren't even close to medium-sized tyrannosaurids.

Just my pure guess.
Or the prey were slower back then?

The tyrannosaurids had a completely different gait than mammalian quadrupeds, so any limit based on running may be very different.
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Old Yesterday, 09:09 PM   #462
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Old Yesterday, 10:29 PM   #463
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Cool Arth!



Originally Posted by Trebuchet View Post
...and mountain gorillas are in a semi-permanent state of flatulence due to the large amounts of gas produced from bacteria aiding their digestion.



Gorillas in the mist...
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Old Yesterday, 11:51 PM   #464
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Portia is the most intelligent arthropod known, by a long shot. P fimbriata being the best studied.
It's a small jumping spider that has "the most varied prey capture techniques of any animal in the world except humans and other simians."
They have very good vision in their two main eyes, more acute than a cat in daylight and 10 times better than a dragonfly.
They hunt other spiders up to twice their own size and quickly develop new tactics to deal with prey in the lab that they could never have encountered in the wild. They are slow and meticulous when stalking their prey.

"Portia species can make detours to find the best attack angle against dangerous prey, even when the best detour takes a Portia out of visual contact with the prey, and sometimes the planned route leads to abseiling down a silk thread and biting the prey from behind. Such detours may take up to an hour, and a Portia usually picks the best route even if it needs to walk past an incorrect route."

"Portia uses trial-and-error to successfully solve a confinement problem (i.e. how to escape from an island surrounded by water) both when correct choices are rewarded and when incorrect choices are punished."

"A Portia can pluck another spider's web with a virtually unlimited range of signals, either to lure the prey out into the open or calming the prey by monotonously repeating the same signal while the Portia walks slowly close enough to bite it."

It tries out, learns and remembers different strategies for dealing with different prey and it does it with only about 600 000 neurons.

Isn't that amazing?
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Old Today, 01:55 AM   #465
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The thread about parasites eating tumors reminded me of parasitoid wasps and the polydnavirus.

It's a virus in a wasp in a caterpillar.

The full genome of the virus is integrated into that of the wasp. The viral proteins are only produced and assembled in special cells in the ovaries of female wasps. The virus is injected into the caterpillar with the eggs and does not replicate, but suppresses the immune system, allowing the eggs and larvae to survive.

It's an old association between the wasp, the virus and the caterpillar, more than 70 million years and it's not sure whether the virus is wholly derived from wasp genes or an existing virus that got incorporated long ago.
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Old Today, 07:53 AM   #466
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The relative size of the orbits of the planets (excuse the simplification to circular orbits). The light red band is the asteroid belt. The sun is nary a dot.

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Old Today, 08:05 AM   #467
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You can calculate PI to a... fair, no great, not super-precise but fair, level of accuracy with a sheet of paper, a straight edge, a pencil, and a handful of matchsticks or similar sized objects.

https://www.sciencefriday.com/articl...opping-sticks/
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Old Today, 08:08 AM   #468
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Originally Posted by pgwenthold View Post
The relative size of the orbits of the planets (excuse the simplification to circular orbits). The light red band is the asteroid belt. The sun is nary a dot.

http://www.internationalskeptics.com...ictureid=10627
But Pluto isn't a planet

This is one of the cooler things on the interwebs: http://joshworth.com/dev/pixelspace/...larsystem.html

The Solar System scaled to the moon being 1 pixel.
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Old Today, 08:11 AM   #469
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You can count to 1023 on your fingers in binary.
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Old Today, 08:13 AM   #470
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Originally Posted by p0lka View Post
You can count to 1023 on your fingers in binary.
You can count to 1,048,575 if you also use your toes.
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Old Today, 08:28 AM   #471
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Originally Posted by p0lka View Post
You can count to 1023 on your fingers in binary.
Which has been, for a very long time, how I prefer to count on my fingers.

Dave
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Old Today, 08:45 AM   #472
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Originally Posted by Cheetah View Post
Portia is the most intelligent arthropod known, by a long shot. P fimbriata being the best studied.
It's a small jumping spider that has "the most varied prey capture techniques of any animal in the world except humans and other simians."
They have very good vision in their two main eyes, more acute than a cat in daylight and 10 times better than a dragonfly.
They hunt other spiders up to twice their own size and quickly develop new tactics to deal with prey in the lab that they could never have encountered in the wild. They are slow and meticulous when stalking their prey.

"Portia species can make detours to find the best attack angle against dangerous prey, even when the best detour takes a Portia out of visual contact with the prey, and sometimes the planned route leads to abseiling down a silk thread and biting the prey from behind. Such detours may take up to an hour, and a Portia usually picks the best route even if it needs to walk past an incorrect route."

"Portia uses trial-and-error to successfully solve a confinement problem (i.e. how to escape from an island surrounded by water) both when correct choices are rewarded and when incorrect choices are punished."

"A Portia can pluck another spider's web with a virtually unlimited range of signals, either to lure the prey out into the open or calming the prey by monotonously repeating the same signal while the Portia walks slowly close enough to bite it."

It tries out, learns and remembers different strategies for dealing with different prey and it does it with only about 600 000 neurons.

Isn't that amazing?
As a longtime spider enthusiast, that is fascinating.
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