Follow the weather

来源: 移花接木于 2024-03-01 08:04:06 [档案] [博客] [旧帖] [给我悄悄话] 本文已被阅读：次 (4603 bytes)

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这次不是google 翻译，是我直接写的中文，也是直接写的英文。

跟着天气预报制定自己的出行或者公平赌博，实际上是在玩概率游戏。上几周我一直尽可能地坐公交车，所以更加关心天气预报，我发现天气预报的准确度极低，夸张点说10%的准确度，不必较真，反正很低就是了。10%的准确度其实一点都不差，别以为我在开玩笑，真的是不差。

适当更正一下，其实吧，天气预报晴天还是大差不差，是雨天预报准确度大约是10%

关于准确度的概率有时候就会比较那什么什么，不让人省心。

先问个问题：最坏的预测准确率是多少？ 1%，2%，0%？

都不是啊，最差的预测准确率是50%, 这是最低的赢率。如果预测准确度高于50%，我们就按照预测出牌straight forward. 如果预测准确度低于50%, 我们就不按预测出牌，"Straight backward"（这个短语是我发明的吗？），运用反向逻辑下注。如果天气预报准确率10%, 预报有雨，我就当它没雨，赢面90%。

本周二，天气预报有雨，我运用反向逻辑，没雨。出门走路坐公交不带雨具，这次那10%赢了，下雨了，我在雨里走了20分钟。第二天，周三，仍然预报有雨，我做出了一个犯兵家大忌的决定：change horses in midstream, 改用了正向逻辑，听信天气预报，开车，在雨里洗车，这次那90%赢了，一滴雨都没下。我浪费一天走路的机会, 车也没洗成。

今天，其实是昨天周四，天气预报早晨就开始下雪，低温。也是这是本冬天最后一个冷天了，我可不想错过，零下10度的温度，我觉得自己舒适活跃。而且我也想在下雪时走路。我又坐公交车了。这次的决定似乎是稳赢不输，下不下雪我都走路。但天气预报概率再次证明与10%不维和。都到了下午了，太阳还是那么灿烂。一直盼到下班雪也没下。

以后还这么玩，也不会采取任何防雨预备措施。

今天天气预报说: Tonight sunshine.

Following the weather forcast or playing fair gamble, what we are really playing is a probability game.

From my last few weeks experience, i.e. I became more weather concerned since I started taking public transportation, I found that my local weather forcast accuracy is about 10%. That's not bad at all. You might think I am joking that I meant 10% is better than 0%. Nope, I am serious, and 10% is no better than 0%.

Probability becomes tricky at certain point.

Q: What is the worst prediction accuracy 1%, 2%, or 0% ?

None of them, the worst is 50%, it is the lowest winning rate. If the accuracy is higher than 50% we follow the prediction, straight forward. If the accuracy is lower than 50% (learned from our statistic) we just reverse our decision from the prediction, "straight backward". We bid with reverse logic. If the weather accuracy is 10% , we do the opposite from what the forcast says we get 90% winning chances.

This Tuesday I used reversed logic ignoring the rain forcast, I should have 90% chances of winning.

But I was caught by the 10% rain. The next day, Wednesday, I changed my horse in midstream, I followed the weather forcast of rain, I drove and expected to get my car washed by the rain, this time fate faved the 90%, i.e. no rain; rain never came down, I lost a day's hiking fun.

Today, the weather said snow and cold, this could be the last cold day of this winter, I didn't want to miss this. My body can be very active at around -10C, and I want to embrace the snow fall. Up to this point the sun still shines. Where is my appointed snow?

Anyway, to me, it is an all winning game, I get my walking in a chill at least, and I won't take any weatherproof action in the future. I am really having fun.