# Rubik's Cubes and Math (Statistics)



## kprox1994 (Jan 31, 2012)

Haven't posted here in quite a while, really busy. But was thinking about how my math homework could be useful in cubing, and how you could see the probability of getting above/below a certain time in a mean. I don't know how to work this for averages though.






Thanks for watching, and please share your thoughts!


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## AvGalen (Jan 31, 2012)

Fun idea, but
1st of all: where is the math?
2nd: you should explain the "2 divided by sqr 5" a bit more

and calculating this for the "drop highest and lowest and then average the rest" will be really hard. This way is fine in reality because other factors such as nerves and skips will play a much bigger factor than math


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## tozies24 (Jan 31, 2012)

I suppose at 1:49 when you draw the graph, the little segments that are above the bell curve or below the bell curve are the really lucky or unlucky cases? (Pops/other things) lol

also, wouldn't that be 4.7 percent not 0.04 percent?

otherwise I thought it was a pretty informative video


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## vcuber13 (Jan 31, 2012)

i would do this very differently


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## kprox1994 (Feb 1, 2012)

AvGalen said:


> Fun idea, but
> 1st of all: where is the math?
> 2nd: you should explain the "2 divided by sqr 5" a bit more
> 
> and calculating this for the "drop highest and lowest and then average the rest" will be really hard. This way is fine in reality because other factors such as nerves and skips will play a much bigger factor than math



Statistics is a part of Math (at least that's what I'm told). We learned this in stats class. The 2 is the std. dev, and the 5 is for the sample size, since it is a mean of 5 that would be the sample size. To calculate the prob for a sample size you need to use the equation std. dev/sqrt of sample size, and insert that where the std. dev is for the normalcdf. 
The drop highest and lowest does sound really difficult, I was just wondering if it was possible.



tozies24 said:


> I suppose at 1:49 when you draw the graph, the little segments that are above the bell curve or below the bell curve are the really lucky or unlucky cases? (Pops/other things) lol
> 
> also, wouldn't that be 4.7 percent not 0.04 percent?
> 
> otherwise I thought it was a pretty informative video



Thanks! Yes those would be unlucky/lucky cases, or just epic fails or wins. The 0.047 is the chance that it will happen out of 1, mult 0.047 by 100 and you get 4.7 percent (out of 100).



vcuber13 said:


> i would do this very differently


 How?


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## JonWhite (Sep 18, 2012)

kprox1994 said:


> The 0.047 is the chance that it will happen out of 1, mult 0.047 by 100 and you get 4.7 percent (out of 100).



First, 0.047 *100 = 470%.

Second, if each day there is a 10% chance of rain in my magical neighborhood, then in a period of two weeks, there will be a 140% chance of rain.


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## Noahaha (Sep 18, 2012)

JonWhite said:


> First, 0.047 *100 = 470%.
> 
> Second, if each day there is a 10% chance of rain in my magical neighborhood, then in a period of two weeks, there will be a 140% chance of rain.



Not sure if trolling, but:

0.047 = 4.7% (you multiplied by 100 twice)

You're wrong about your second comment too. The odds of rain are actually 1-(90/100)^14 in that case, since probabilities are multiplied not added. You have to calculate the chance of every day not having rain and then subtract it from one.

Also, just based on a logic standpoint nothing can have a probability greater than one, and even so, clearly if there is a 10% chance of rain every day there is a chance (and a very good one) that it never rains.


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## uberCuber (Sep 18, 2012)

I think it was pretty clear what kprox intended that quoted statement to mean, but technically, that first statement that JonWhite wrote is correct. 0.047 = 4.7%, and so 0.047*100 (which is technically what kprox wrote, "mult 0.047 by 100") = 470%


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