Re:Ferromagnetic half levitation of LK-99-like synthetic sam...
by dcow on Tuesday August 08, 2023 @10:21AM
(#37049374)
What? Your model doesn't make any sense if you don’t know how to combine probabilities.
Furthermore, you can’t just say “I understand things semantically different than everyone else talking about probabilities so when I say the probability of two events happening is 20% I actually mean something completely different and my math works this way I invented to describe why my messy naive intuitions about probability don’t match the reality of how probability works”.
K event = Kim says Material L is RTSC
D event = DFT says L is RTSC
S event = L is actually RTSC
we have assumed P(S/K) and P(S/D) are each 0.1, though we could have chosen other numbers for them as well.
We want to estimate P = P(S/(K and D))
P = P((K and D)/S)P(S)/P(K and D)
Assuming Kim and DFT are in the business of making positive predictions, they always get it right when L is actually RTSC.
so P(K/S),P(D/S) and P((K and D)/S) are all taken as 1
hence P = P(S)/P(K and D) = P(S)/(P(K)P(D/K)) = P(S/K)/P(D/K) = 0.1/P(D/K)
(similarly, P = P(S/D)/P(K/D) = 0.1/P(K/D))
But ofcourse we dont know P(D/K) or P(K/D). We could check historical data on how often D aligns with K, a messy exercise at best. Say they dont perfectly align, then the conditionals are less than 1,and P>0.1. Even intuitively when K (or D) gets additional support in the form of D (or K), your P should increase, not decrease.
If we assume D and K align on average, then P(D/K) or P(K/D) is 0.5, and we get P = 0.2.
You may estimate everything above differently, thus getting a different P. You can also come up with your own way of modelling this. I came up with my particular estimate to understand how frequently should i follow the news, and care about the whole thing. You should model it according to your usecase.