1. low-pressure --> local area 2. low-presssure --> rainfall (70%) --> at Local area 3. low-pressure --> thundershowers --> at Local area & at resent time period (spiring, now)
gracehu 发表于 2003-11-29 10:17
21. A low-pressure weather system is approaching Plainville; rainfall results ...
1. Correlation never proves causality
2. 2 things happened coincidentally with one and another does not prove any causality either.
3. When A happen, B, and C also happened, it does not mean A is the cause for both B&C, it could be A is " coincidentally happened when B cause C or C cause B.
Core question: The determining factor of the probability that plainville will have a thundershower soon.
Well... Thundershower means thunder and rainfalls, so all we have to do is to calculate the possibilities of exactly when thunder happens, rainfalls also happens at spring seasons.
So let us say that spring seasons are 4 months as total, which are 120 days, and within those 120 days, we have exactly 84 days ( 120 * 0.7 ) are days with rainfalls, and if we do have a exact numbers and dates of thunder happened within those 120 days, we can know within that 84 days of rainfall, when do we have the day with not only rainfalls but also thunders. lets make up a number as 20 days, both rain and thunder.
In that sense, the percentage of spring rainfalls in Plainville that are thundershower could be calculated as 20/84.
C. Please please please ensure that you are not going to be distracted by " low pressure systems ". If you are figuring the percentage of thundershowers due to low pressure system, then you can only have use that outcome to versus the percentage of thundershowers " not due to " low pressure system. However, even we do have the exact answer from that versus relationship, we still can't determine the probability of the thundershower at plainville.
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发表于 2008-6-1 20:34:00
