Porcellio Card ??

[Whispers]

It still makes no sense to me.??Maybe it's because I like to see things with a definite outcome.??What you wrote, Maha, is obvious to anyone (though it takes a keen mind to see the phenomenon graphically), but the logic behind the formula for finding out the probability of obtaining something with a fixed probability after attempting x amount of times alludes me.

Yeah, it's easy to think, "I've killed millions of these things, I can't fail with this next one," but that reasoning doesn't seem correct to me.??It doesn't seem logical.??I now know the 1-(1-probability)^x formula--thank you, Ayu--but it doesn't make sense.

Can anyone explain this to me?

What I mean by "explain" is this:

I have a tome titled "The Dog Owner's Home Veterinary Handbook."??In one of the appendices it has a list of approximate "dog" years compared to human years.??I noticed that in the first year of life a dog ages the equivalent of 15 years.??In the second year of life a dog ages nine years, bringing it's "age" to 24.??Every year after the second a dog ages four years - 28, 32, 36, etc..??After doing a bit of math I created the formula for finding a dogs age past the first year:

• d = 4h + 16,

where d = age in dog years and h = age in human years.??The math checked out, but I was wondering why this specific formula was correct.??The four is obvious - a dog ages four years every year of life past two human years; but why sixteen???Where did that come from?

After a bit of thought and looking at a few more numbers I saw the reason.??We are multiplying by four and adding sixteen for every year past the first.??The progression from the first to second year is nine "dog" years.??Nine is not divisible by four (it is, but we're working with integers).??When we divide nine by four we get 2 with a remainder of one (or 2.25 with 25% of four being one - hooray!).??We then add this remaining 1 to 15 to make 16.??So, what we really have is:

• d = 4h + 15 + 1.

Now it makes sense!??=D


I tried making sense of the probability thing.??I envisioned a bag of 100 marbles.??One of these marbles is black whereas the other 99 are white.??I won't bore you with the math, but I'm still working it out.??Maybe it's exponents I'm having a problem with???I never fully understood their usage.??Why would you raise the unfavorable percentage to the power of the number of attempts as opposed to multiplying the unfavorable percentage by the number attempts instead???It seems to me that If I've killed three monsters I've a three-fold probability not a %^3 probability as I've tried three times.??If I've spent two dollars three times I've spent 2*3 dollars not 2^3 dollars.??If I tie my shoe four times every time I jog and I jog two times a day (I wish xp) then I tie my shoe whilst jogging 4*2 times a day not 4^2 times a day.??I believe I'm making sense here.??The number of tries exponentially raising the probability as opposed to multiplicatively is just...

I hope someone can explain it to me.??I'll hopefully figure it out for myself if no one does, though.??=/

[EDIT]

I'm not saying the formula is incorrect. I'm just saying it doesn't make sense to me. Please don't infer incorrectly.