## Tuesday, February 24, 2009

### Correlation in a nutshell (C/O Wired story today)

To understand the mathematics of correlation better, consider something simple, like a kid in an elementary school: Let's call her Alice. The probability that her parents will get divorced this year is about 5 percent, the risk of her getting head lice is about 5 percent, the chance of her seeing a teacher slip on a banana peel is about 5 percent, and the likelihood of her winning the class spelling bee is about 5 percent. If investors were trading securities based on the chances of those things happening only to Alice, they would all trade at more or less the same price.

But something important happens when we start looking at two kids rather than one—not just Alice but also the girl she sits next to, Britney. If Britney's parents get divorced, what are the chances that Alice's parents will get divorced, too? Still about 5 percent: The correlation there is close to zero. But if Britney gets head lice, the chance that Alice will get head lice is much higher, about 50 percent—which means the correlation is probably up in the 0.5 range. If Britney sees a teacher slip on a banana peel, what is the chance that Alice will see it, too? Very high indeed, since they sit next to each other: It could be as much as 95 percent, which means the correlation is close to 1. And if Britney wins the class spelling bee, the chance of Alice winning it is zero, which means the correlation is negative: -1.

(Original Wired story is about the math behind the mortgage crisis in the US and can be found here)

## Saturday, February 21, 2009

### My Draft of Chapter 1

http://educ864gp.blogspot.com/2009/02/draft-of-first-chapter.html

## Sunday, February 8, 2009

### Not just for Monkeys

So... If you thought the monkey was cool...
Have a look at Matell's "Mind Flex"
available later this year for about \$80

Hello all,

in response to the query about uploading documents to a blog, as I see it, there are a couple of choices.

a) you can convert your doc to a picture and then upload it, as you would any image.
b) the other is to use some kind of 3rd party site and then create a post with an embed code. I have used Scribd.com in the past for this. I've pasted an example below of how it works.

(The reader can view the doc full-screen, or print it or download it according to his/her needs.)

Garage Band 3 Steps

## Wednesday, February 4, 2009

### Blogging PDF/MS Word Documents

Hi Gordon,

Could you post a link to the site where we can upload our documents for Maureen to view.

Thanks

## Tuesday, February 3, 2009

### Diversion: Ze Frank

A few people wanted the link to Ze Frank's site. Check out the Frog. Make sure your mic is on. Use this as a reward for when you finish your assignment.

### Ed.Tech Potluck

What do you think about having a potluck some time?

## Sunday, February 1, 2009

### RefWorks Write-N-Cite "how to"

Start by viewing my screencast "how to" at: http://screencast.com/t/sr9lZFoZ
Notes from the above screencast: