IPB

Welcome Guest ( Log In | Register )

 
Reply to this topicStart new topic
ABX P Value, Correct Equation
cabbagerat
post Sep 22 2004, 12:14
Post #1





Group: Members
Posts: 1018
Joined: 27-September 03
From: Cape Town
Member No.: 9042



I definately remember reading a discussion on the correct calculation of the ABX p-value (probability you were guessing) a while back but a couple of searches and a read through the FAQ were unhelpful. From my limited stats knowledge (half a semester on probability) I came up with (for p correct from n trials) nCk*(0.5)^n*(0.5)^(n-k) which simplifies to nCk/2^n. This doesn't seem correct to me.

What is the correct equation for working this out?


--------------------
Simulate your radar: http://www.brooker.co.za/fers/
Go to the top of the page
+Quote Post
Omion
post Sep 22 2004, 21:02
Post #2





Group: Developer
Posts: 432
Joined: 22-February 04
From: San Diego, CA
Member No.: 12180



I don't know if there's an easier mathematical equation for it, but this one works:

n=number of trials
k=number correct
q=temp variable

sum( q=0 to n-k : (nCq) / (2^n))
For n=5 and k=4, this gives 1/32 + 5/32 = 3/16 ~ 0.1875

[edit: deleted quote]

This post has been edited by Omion: Sep 22 2004, 21:03


--------------------
"We demand rigidly defined areas of doubt and uncertainty!" - Vroomfondel, H2G2
Go to the top of the page
+Quote Post
kjoonlee
post Sep 22 2004, 22:05
Post #3





Group: Members
Posts: 2526
Joined: 25-July 02
From: South Korea
Member No.: 2782



http://www.hydrogenaudio.org/show.php/showtopic/14679


--------------------
http://blacksun.ivyro.net/vorbis/vorbisfaq.htm
Go to the top of the page
+Quote Post
cabbagerat
post Sep 23 2004, 07:40
Post #4





Group: Members
Posts: 1018
Joined: 27-September 03
From: Cape Town
Member No.: 9042



Thanks Omion and kjoonlee, that's just what I was looking for.


--------------------
Simulate your radar: http://www.brooker.co.za/fers/
Go to the top of the page
+Quote Post

Reply to this topicStart new topic
1 User(s) are reading this topic (1 Guests and 0 Anonymous Users)
0 Members:

 



RSS Lo-Fi Version Time is now: 20th December 2014 - 09:24