Sunday, February 08, 2009

Math made me laugh. 

Hat tip to: Musings From a Catholic Bookstore.

, this new law to keep lead away from kids, could do much economic collateral damage I just can't help laughing. Read here
Searching for certainty is an entirely noble human endeavor. We long for the days when we were younger, when Mom or Dad could hold us in their arms and we would know we were safe. As we become adults, we venture out into the cold, uncertain world, and eventually we learn to live there by sticking to the course we feel most likely to bring a good outcome.

Groups like Consumer's Union seem to me to be taking an immature approach to the problem of lead in children's products. They wanted CPSIA because they believed it would make us safe from all lead, forever. Like little children, they wanted Mommy and Daddy Congress to make it all go away, and they are mad at that bad bad lady Nancy Nord for not doing what Mommy and Daddy said. If only Congress had that power. Congress has the power to make laws, but they do not have the power to make people 100% safe. Even if CPSIA is fully implemented, we will not be 100% safe from lead. Setting aside the fact that most lead exposure comes from lead in house paint, let's take a look at why this is.

We are going to use what nerds like me call a "stochastic," or probability-based, approach. Probability is the most counter-intuitive branch of mathematics, so I'll do my best to explain this approach in layman's terms.

Suppose a clothing manufacturer, let's call him Ben, buys 10,000 metal snaps from a snap manufacturer, Jessica. Ben wants assurances that Jessica's snaps are CPSIA compliant to the 100ppm standard. So Jessica pulls out her XRF gun and tests 100 snaps (that's 1% of the snaps), and they all test around 60ppm, near but under the lead content limit.
Read the whole thing. It's great. Unless you aren't a math geek, in which case, I don't know what to say to you.

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