July 19, 2006

Running for beginners.

14 years ago, I was introduced to the process of normalising grades. Professors “fit” students’ marks into a normal distribution and assign grades based on that. (I still don’t know how they do it). Since then, I’ve encountered normalising a lot. My performance at work is normalised. I normalise my song ratings and movie ratings. I’ve normalised all kinds of things at work: lead-time of delivery of fans, movements in savings account balances, calls to a call centre, demand for a resource… you name it. ...

I rate movies on a scale of 1 (bad) to 5 (good). This is an absolute scale. Initially, I assumed that I would watch as many good movies as bad ones. So I'd have about as many 1s as 5s, and 2s as 4s. But, when I looked at my ratings for movies over the last year, I had far more 4s than 2s. My movie ratings were not normal. ...

I was working with the treasury of a bank. They were trying to estimate how much money could flow out of their savings account in a day, worst case. I took their total savings account balance at the end of each day and found the standard deviation. I took thrice the standard deviation, and said, “You can be 99.7% sure that your daily loss won’t be more than 1.5% of the balance.” ...

I've jumbled up 3 stills from an old movie. You can move the jumbled blocks around, like a jigsaw. Can you guess the actors and the movie?