Comments on: Can You Recognize Random?

By: 7 Quick Takes (11/23/12)

7 Quick Takes (11/23/12) — Fri, 23 Nov 2012 06:19:09 +0000

[…] in how one relates to every person one meets, man or woman. — 7 —And, finally, via dy/dan, a nice video on our intuitions about randomness: For more Quick Takes, visit […]

By: Themes | 5 Megapixels

Themes | 5 Megapixels — Fri, 10 Feb 2012 02:54:50 +0000

[…] are horrible at making random numbers. If you ask students to flip a coin 200 times and record the results, you can tell who cheated or […]

By: dy/dan » Blog Archive » Khan Academy Is On Some Kind Of Spending Spree

dy/dan » Blog Archive » Khan Academy Is On Some Kind Of Spending Spree — Fri, 13 Jan 2012 20:29:02 +0000

[…] Now Brit Cruise, whose exemplary work with videos and math instruction was featured in these pages a couple of weeks ago. For me, this has all the drama of some kind of skin graft or organ transplant where no one has any […]

By: Brit Cruise

Brit Cruise — Wed, 11 Jan 2012 16:17:37 +0000

Hi Jared,

Thanks for that point. The video doesn’t explicitly say that heads = 1 and tails = 0 vs heads = toggle, tails = no toggle. I’m about to publish this full chapter and will make that distinction in the voice over.

Good day!

Brit

By: Stephen Castleden

Stephen Castleden — Wed, 04 Jan 2012 01:33:54 +0000

Hi,

I like the videos by brit. Interestingly when I first clicked on the link from here to brit’s site there was a strange video (not by brit) on his site, the youtube link is

http://www.youtube.com/watch?feature=player_embedded&v=4jL2f-2vY1Q

I think brit may have removed the link…(hopefully).

It generates an interesting question about mathematics and propaganda…(I am a vexed athiest by the way!!!)

Thanks for all the good work,
Steve.

By: Carl Malartre

Carl Malartre — Fri, 16 Dec 2011 20:53:45 +0000

That video is awesome!

I like Mr. K’s idea:
/?p=6359#comment-258308

What I like in the video is that it focus on 1 and 0, on/off.

I’m trying this story line:
“There’s a new government program to screen people at the airport. A machine is randomly picking one out of two people to be searched on. Some people complain that they are searched on more often than other. Your group is selected to independently prove this. Unfortunately, the only data the airport keep and can share with you is a series of 1 and zeroes.”

By the way, they do that in Mexico. You press a green button, and it’s pseudo-random, but better than nothing. I was looking for a reference and found that article by Keith Devlin:
http://www.maa.org/devlin/devlin_05_02.html

Carl

By: Bowen Kerins

Bowen Kerins — Thu, 15 Dec 2011 03:36:03 +0000

Hey, I love this. (Seems like the video could use some pauses or “Act 1 / 2 / 3” breaks, but those are easily added when playing the video with students.)

We used a similar task to lead off the Park City Math Institute course back in 2007:

http://mathforum.org/pcmi/hstp/sum2007/morning/bowen/day1handout.pdf (top of page 2)

This was a big hit and really needs a lot of flips! (We used 240 flips so we could break it up into chunks like this video does.) Other strategies included counting the number and distribution of “runs” (fake data tends to have more, shorter runs, since how could it come up heads 8 times in a row amirite) and the distribution of heads and tails when the data is grouped (by 2s, 3s, 4s, etc).

The overall course directory (http://mathforum.org/pcmi/hstp/sum2007/morning) includes several groups’ real and fake data, some labeled, some unlabeled.

By: Jared Derksen

Jared Derksen — Wed, 14 Dec 2011 22:11:07 +0000

I used this video in my AP Stats class. I feel that it has some flaws. The random mechanism isn’t clear. A little switch, as shown in the video, toggles a light between on and off. But the implication of the string of 1’s and 0’s seems to be that heads you leave the light on and tails you turn it off. Or is the rule: heads you toggle the switch and tails you leave the switch in its current state?

I think the video would be improved it made the connection between heads/tails and on/off more clear.

By: LL

LL — Wed, 14 Dec 2011 22:01:39 +0000

That is a really interesting way to look at whether the flips are random or not. You would also find that most people will not write 5 heads or 5 tails in a row, but this will almost always happen at least once when you fip a coin 100 times. Another thing to look at is the conditional probabilities: I think you would find that tails is much more likely to follow 2 consecutive heads if a person is writing the list.

By: Jason Dyer

Jason Dyer — Wed, 14 Dec 2011 17:25:44 +0000

Quick, classroom-ready version:

Have them pick a “random” number from 1 to 1000.

Plot the class distribution.

It will (if random) be linearly distributed, but it will instead (due to psychology) be logarithmic.