The Jarmidor: Performance Monitoring

I was up at Pet Smart buying cat food since the cats have managed to eat us out of house and home yet again and I happened to be looking at the reptiles.

Suddenly, inspiration struck. Reptiles need the right temperature, because they are cold blooded, but they also live in a humid, humid rainforest. What else lives in a tropical climate?

Free range cigars, that’s what.

I wandered over to the reptile aisle and sure enough there were enough hygrometers to monitor every planet in the solar system. (About 9). Now, people commonly complain the hygrometer in their humidor is crap and can be as far as 10% off. To figure out if we’re buying a good one or not we need to compare. Instrumentation is one of those things where you don’t need to test it to make sure it works, the majority of it merely has to agree. In other words, if the standard deviation is small, then we know the instrument is probably mostly correct and we know about how far off they can be. For this trick, we try to buy one representing the mean value.

In my case, out of 9 of these, 8 of them agreed the humidity in the store was between 40% and 42%. One of them said 50%, so this one obviously is in error. Upon tapping them, the needle would typically settle back into the same place, so we know none of them are stuck like this and the needle is free floating. I tried to power up a digital hygrometer but it was disabled. Comparing it to the one the store uses in their cages, the humidity was 41%. I was willing to accept any hygrometer that read between 40% and 42%, which was almost all of them.

For $5 and a sample size large enough to find the ones obviously misadjusted, it’s a steal.