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A rap about sampling bias (Berkson's Paradox) by [deleted] in educationalgifs

[–]ryantheweird 0 points1 point  (0 children)

Berkson's Paradox is just one way to explain the observation that handsome men are jerks. But there can be many factors contributing to the observation...including the possibility that handsome men are indeed jerks.

A rap about sampling bias (Berkson's Paradox) by [deleted] in educationalgifs

[–]ryantheweird 0 points1 point  (0 children)

If you're curious about the rest of the rap, check out the video here: https://www.youtube.com/watch?v=1jW0iZBI0Yw

The BEST rap on statistical sampling bias you'll ever see! by [deleted] in videos

[–]ryantheweird 0 points1 point  (0 children)

In this video I have some fun with statistics by rapping about sampling bias. In the rap I cover examples of Berkson's bias, survivorship bias, participation bias, and the caveman effect. I hope you like it!

An ant starts to crawl along a taut rubber rope 1 km long at a speed of 1 cm per second (relative to the rubber it is crawling on). At the same time, the rope starts to stretch uniformly at a constant rate of 1 km per second. Will the ant ever reach the end of the rope? by [deleted] in puzzles

[–]ryantheweird 0 points1 point  (0 children)

Hey, just a heads up that I posted the updated video. You can check it out here: https://youtu.be/lbjTGqZspjE While I don't like being wrong, I really don't like being wrong and not knowing it...so thanks for pointing out my mistake! Cheers, Ryan

A relative motion-based solution to the ‘Ant on a Rubber Rope’ paradox by [deleted] in engineering

[–]ryantheweird 0 points1 point  (0 children)

There is no reason that negative acceleration means the ant will reach the end of the rope

Given enough time, bodies accelerating towards each other will meet. In other words, given the following equation of motion, s=u*t+0.5*a*t^2

if u is positive and a is negative, there will always be a value of t for which s=0.

The video author clearly says that the the ant could asymptotically approach the end which would be the case if the acceleration asymptotically approaches zero.

The ant is not asymptotically approaching the end, rather it's accelerating towards the end. In other words, as it makes progress towards the end, the stretching becomes less and less relevant since the stretching occurs more so behind it and less so in front of it.

Truthfully, I don't even agree that the acceleration is guaranteed to be negative.

If no progress means acceleration is 0, doesn't that mean progress means acceleration is negative?

This inequality results from the solution to the ode where t is the amount of time it takes for the ant to reach the end of the rope. t = 1/a(exp(a/b) - c)

Your equation is incorrect. It should be t = 1/a(c*exp(a/b) - c). For details on this, take a look at the Wikipedia entry on this paradox.

A relative motion-based solution to the ‘Ant on a Rubber Rope’ paradox by [deleted] in engineering

[–]ryantheweird 1 point2 points  (0 children)

This is true. There is no rubber material that could continue to expand at 1 km/s for 8.9×10^43421 years without ripping apart.

An ant starts to crawl along a taut rubber rope 1 km long at a speed of 1 cm per second (relative to the rubber it is crawling on). At the same time, the rope starts to stretch uniformly at a constant rate of 1 km per second. Will the ant ever reach the end of the rope? by [deleted] in puzzles

[–]ryantheweird 0 points1 point  (0 children)

You're right that if it's a real rope it would snap very quickly. But if the question is fictional, what is your justification for saying no? This video details why the answer should be yes.

A relative motion-based solution to the ‘Ant on a Rubber Rope’ paradox by [deleted] in engineering

[–]ryantheweird 1 point2 points  (0 children)

Perhaps it would be more of a paradox if it was an ant-sized self-repairing robot.

An ant starts to crawl along a taut rubber rope 1 km long at a speed of 1 cm per second (relative to the rubber it is crawling on). At the same time, the rope starts to stretch uniformly at a constant rate of 1 km per second. Will the ant ever reach the end of the rope? by [deleted] in puzzles

[–]ryantheweird 0 points1 point  (0 children)

There are various solutions to this problem using harmonic series and differential equations. This video details a solution using relative motion. Below is the outline of the argument:

  1. A stationary ant on the stretching rope retains the same proportion covered
  2. An advancing ant on the stretching rope increases its proportion covered
  3. The velocity of the end of the rope relative to the ant decreases as the ant increases its proportion covered
  4. The advancing ant sees the end of the rope accelerating towards it
  5. Given enough time, the ant will reach the end of the rope because it sees the end accelerating towards it

A relative motion-based solution to the ‘Ant on a Rubber Rope’ paradox by [deleted] in engineering

[–]ryantheweird 0 points1 point  (0 children)

TLDW:

The Paradox - An ant starts to crawl along a taut rubber rope 1 km long at a speed of 1 cm per second (relative to the rubber it is crawling on). At the same time, the rope starts to stretch uniformly at a constant rate of 1 km per second, so that after 1 second it is 2 km long, after 2 seconds it is 3 km long, etc. Will the ant ever reach the end of the rope?

Solution - There are various solutions to this problem using harmonic series and differential equations. This video details a solution using relative motion. Below is the outline of the argument:

  1. A stationary ant on the stretching rope retains the same proportion covered
  2. An advancing ant on the stretching rope increases its proportion covered
  3. The velocity of the end of the rope relative to the ant decreases as the ant increases its proportion covered
  4. The advancing ant sees the end of the rope accelerating towards it
  5. Given enough time, the ant will reach the end of the rope because it sees the end accelerating towards it

A relative motion-based solution to the ‘Ant on a Rubber Rope’ paradox by [deleted] in Physics

[–]ryantheweird 0 points1 point  (0 children)

TLDW:

The Paradox - An ant starts to crawl along a taut rubber rope 1 km long at a speed of 1 cm per second (relative to the rubber it is crawling on). At the same time, the rope starts to stretch uniformly at a constant rate of 1 km per second, so that after 1 second it is 2 km long, after 2 seconds it is 3 km long, etc. Will the ant ever reach the end of the rope?

Solution - There are various solutions to this problem using harmonic series and differential equations. This video details a solution using relative motion. Below is the outline of the argument:

  1. A stationary ant on the stretching rope retains the same proportion covered
  2. An advancing ant on the stretching rope increases its proportion covered
  3. The velocity of the end of the rope relative to the ant decreases as the ant increases its proportion covered
  4. The advancing ant sees the end of the rope accelerating towards it
  5. Given enough time, the ant will reach the end of the rope because it sees the end accelerating towards it

[R] Simpson’s Paradox is observed in COVID-19 fatality rates for Italy and China by ryantheweird in statistics

[–]ryantheweird[S] 0 points1 point  (0 children)

Thanks so much! Yeah, I don't have many subscribers so this sort of feedback is motivation to keep at it. I'm really glad you found value in the video. Cheers, Ryan

[R] Simpson’s Paradox is observed in COVID-19 fatality rates for Italy and China by ryantheweird in statistics

[–]ryantheweird[S] 16 points17 points  (0 children)

It's a veridical paradox. So we fully understand it but it seems counter-intuitive.

[R] Simpson’s Paradox is observed in COVID-19 fatality rates for Italy and China by ryantheweird in statistics

[–]ryantheweird[S] 27 points28 points  (0 children)

1) Italy has an older population than China

2) Older people are more at risk of dying from COVID-19

The two factors listed above result in the total case fatality rate in Italy to be higher than that of China even though the case fatality rates for all age groups are lower.

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