My Math Forum  

Go Back   My Math Forum > College Math Forum > Advanced Statistics

Advanced Statistics Advanced Probability and Statistics Math Forum

LinkBack Thread Tools Display Modes
February 8th, 2010, 08:19 AM   #1
Joined: Feb 2010

Posts: 1
Thanks: 0

Calculate probability value


I found a page yesterday and i'm trying to figure it out how to calculate it like he did.

And before i continue, yes, formulas are there but i have no idea how to use them..

This is a part of article URL with formulas:

This is bigger picture of what i'm trying to calculate like he did:

This is the starting/raw data:
125/401 => 31.2% (point average for Original)
160/411 => 38.9% (point average for Combination 11)
143/453 = > 31.6% (point average for Combination 7)

Confidence level is 80%.

What i've tried and figured it out so far:

I know how to get "Sample proportions", that's an easy one
125 / 401 = 0,3117
160 / 411 = 0,3893

"Difference between sample proportions" is also simple:
You take the higher number:
0,3893 - 0,3117 = 0,0776

"Standard error of difference", no idea how to get that.

"z-value", I know, its:
0,0776 / 0,0334 = 2,325

But since I don't know how to calculate "Standard error of difference", getting
"z-value" is impossible.

And then, how on earth once you have all the data, do you calculate "Probability
value for the test".

I've probably spend like 5 hours so far searching the net for formulas and their explanation of "p" and similar and haven't found much that can calculate those two missing things.

Any help would be nice.
Geteburg is offline  

  My Math Forum > College Math Forum > Advanced Statistics

calculate, probability

Thread Tools
Display Modes

Similar Threads
Thread Thread Starter Forum Replies Last Post
How to calculate probability of Pocket Pair in Poker WhiteLabel Probability and Statistics 4 January 25th, 2014 11:21 AM
Use a tree diagram to calculate the probability alfred_oh Advanced Statistics 0 May 3rd, 2013 06:43 AM
How to calculate this kind of probability? decly Advanced Statistics 4 December 27th, 2011 02:54 AM
How to calculate dice probability? nossrannug Probability and Statistics 4 April 18th, 2011 03:20 PM
calculate risk of ruin (statistics & probability) sergeyrar Probability and Statistics 0 February 4th, 2011 07:36 AM

Copyright © 2019 My Math Forum. All rights reserved.