Tuesday, February 24, 2009
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
Follow this link to read my draft of Chapter 1. I welcome any comments you might have!
Tuesday, February 10, 2009
Monday, February 9, 2009
Sunday, February 8, 2009
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
Tuesday, February 3, 2009
Sunday, February 1, 2009
Notes from the above screencast:
Step 1: login to RefWorks.
Step 2: install local Write-N-Cite III
Step 3: configure RefWorks proxy info for Write-N-Cite III
Step 4: open Write-N-Cite (from within Word) and start inserting references into Word.
Step 5: generate APA bibliography