Any math/stats gurus?

Nov 3, 2007
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Suppose I have a bunch of coins, all of which have some type of biased or unbiased weighting. For instance, a coin could come up heads 75% of the time, 50%, 25%, 5%, 0%, etc.

I am given a target heads bias. (e.g. 45%).

I want to classify the coins into either one of two classes: those coins with a heads bias above/at this target, and those coins with a heads bias below it.

I can flip each coin as many times as I want, but I want to find out the minimum number of flips I need per coin in order to do this classification. THAT IS:

(a) how many flips do I need so that the coin can be classified at all; and

(b) how many flips do I need to classify the coin to be above or below the target bias.

(a) and (b) are probably the same (I think).

It is ok if a confidence parameter is needed. e.g. I am 90% confident that this coin can be classified at all.


Someone said something about the inverse binomial or geometic distributions, but I am not sure if those are applicable here.
 

us3rnotfound

Diamond Member
Jun 7, 2003
5,334
3
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When you entered this site, did you notice a sign that said "Free Homework Help?"

anandtechuser07: "No."

You know why?

anandtechuser07: "no :\."

BECAUSE HELPING NOOBS WITH HW ISN'T ANADTECH'S FVCKING BUSINESS, THAT'S WHY!

/pulp fiction
 
Nov 3, 2007
105
0
0
Originally posted by: us3rnotfound
When you entered this site, did you notice a sign that said "Free Homework Help?"

anandtechuser07: "No."

You know why?

anandtechuser07: "no :\."

BECAUSE HELPING NOOBS WITH HW ISN'T ANADTECH'S FVCKING BUSINESS, THAT'S WHY!

/pulp fiction


This isn't a homework question. It's an abstract representation of a problem I need to solve as part of an optimisation scheme for a Fortune-500 company.
 

nismotigerwvu

Golden Member
May 13, 2004
1,568
33
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Normally I'd put my stats minor to use here but I'm currently doing bio lab writeups and simply just killing some time while my printer churns out graphs so I'm going with the teach a man to fish mentality

http://en.wikipedia.org/wiki/B...on_confidence_interval

Look at the normal approximation section. Everything you need is there with a better explanation than I can give. P(hat)...the P with the carrot on its head :)...is the expected probability (think percent...like x many times/ n number of tries) The Z score you should use here is 1.96 (which is derived from a 95% confidence level)
 

tfinch2

Lifer
Feb 3, 2004
22,114
1
0
Originally posted by: anandtechuser07
Originally posted by: us3rnotfound
When you entered this site, did you notice a sign that said "Free Homework Help?"

anandtechuser07: "No."

You know why?

anandtechuser07: "no :\."

BECAUSE HELPING NOOBS WITH HW ISN'T ANADTECH'S FVCKING BUSINESS, THAT'S WHY!

/pulp fiction


This isn't a homework question. It's an abstract representation of a problem I need to solve as part of an optimisation scheme for a Fortune-500 company.

Why should you get paid for me to do your job?

EDIT: Man I fucked that one up. :laugh:
 
Nov 3, 2007
105
0
0
Originally posted by: nismotigerwvu
Normally I'd put my stats minor to use here but I'm currently doing bio lab writeups and simply just killing some time while my printer churns out graphs so I'm going with the teach a man to fish mentality

http://en.wikipedia.org/wiki/B...on_confidence_interval

Look at the normal approximation section. Everything you need is there with a better explanation than I can give. P(hat)...the P with the carrot on its head :)...is the expected probability (think percent...like x many times/ n number of tries) The Z score you should use here is 1.96 (which is derived from a 95% confidence level)

Thanks. You have taught a man to fish today.