Emulate BETADIST function

[mark14]

Hi everyone,

I have another application that I'm developing in Oracle Application Express using Oracle 10g. I developed a 'prototype' of the Oracle application in Excel and used the BETADIST function in this prototype. However, Oracle doesn't have this function, and I basically need to re-write it.

I've read all the documentation on the BETADIST function and how to use it in Excel, so I have a pretty good handle on that. I understand that you provide your x, alpha, beta, and optionally, lower and upper bounds, and the function returns the cumulative beta probability density function.

For example, =BETADIST(0.2,1.57,2) gives me 0.1803.

The problem is, I'm no statistician, and have no idea what it is doing behind the scenes to get the 0.1803 value in order to recreate it. I've checked the Wikipedia pages, among others, and all of those formulas are greek to me.

Can anyone help break down this function for me and explain how that value is logically derived in my example above, using those numbers? That will greatly help me figure out how to rewrite it.

Thanks in advance!
Mark

 

[dalexx01]

Deleted

 

[aarvi]

Hi Mark,


Your post could be a saver for me...can you pls help me with the code you came up with for the Oracle PL/SQL code for the calculus equivalent? I am having a tough time since I need to implement the P value formula in an Oracle/ Pl-sql solution.


P Value = [ 1/ ( (√df) Β(1/2,df/2) ) ] lt->-t to t ∫ ( 1+ x²/df)(-(v+1)/2) .dx
Where df = degrees of freedom x = T-Value


Your help is MOST APPRECIATED!
Thanks