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08-12-2012, 12:54 AM
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Originally Posted by theoil View Post
It was very hot the first 15 days of April hitting 30 degrees every single day without a drop of rain.

On the sixteenth of April a cold front moved in and the high every day was plus 10 but there was still no rain until the final two days of the month when it just poured.

The meteorologist on the local TV station did his monthly wrap up on May 1st by announcing that April was a typical month with an average 20 degree temperature and 85 mm of rain.

I carried my unbrella with me most of the month but was awfully hot in my wool sweater for the first two weeks and a pretty chilly the last two. I forgot my unbrella the last two days of the month and got drenched.

Looking back at the averages though I have to agree that it was a pretty typical and predictable month of weather. Of course if it wasn't I could just go to annual weather averages which would give me more data points. With an average high annual temperature of 12 I would know a lot more about how to dress every morning when I got up.
That's wrong.

The PDO disbelievers would expect the hot weather to continue forever and use the 15 days as proof. The PDO users would expect the average temperature over the next 15 days to be 20, for an average of 25 degrees.

If you flip a coin 100 times and it comes up 75 heads and 25 tails, you don't bet that the next 100 will be 75 tails and 25 heads. You bet that there will be 50 heads and 50 tails, or 125 and 75 total. Flip the coin until you have 1000 results and the PDO users would expect there to be 525 heads and 475 tails. Do it until there are 10,000 results and the expected split is 5025 and 4075.

If you flip that coin 1 million times, the expected result would be 500,025 heads, 499,975 tails. Instead of 75% of results being positive, only 50.0025% are.

Hynh is offline   Reply With Quote