what is the formula of r2 in the neural network toolbox ?ı cant find

ı find a formula that 1-ssresid/sstotal but it equal to 0,9771 but toolbox gives me 0.988893361178763 for example ı type to command window regression(a,b) it gives me the same result 0.988893361178763 but ı cant find the formula which gives this result in the neural network toolbox

[Jan]

Please could you explain how you type in the strange character for the uppercase "i"?

[ferhat gecer]

ooh! its very very important isnt it

Answer 1

[Greg Heath]

>ı find a formula that 1-ssresid/sstotal but it equal to 0,9771

Exactly how are you calculating ssresid and sstotal?

> but toolbox gives me 0.988893361178763

What Toolbox?

> for example ı type to command window regression(a,b) it gives me the same result 0.988893361178763 but ı cant find the formula which gives this result in the neural network toolbox.

NNTB does not contain the formula.

Recheck your ss calculations.

Hope this helps.

Greg

[ferhat gecer]

Last nigt ı fought the formula and ı noticed that the neural network toolbox compute R it doesnt compute R2 and the formula is a complex formula in Chapras book. 1- ssresidual/sstotal gives R2 and it computes roughly but the complex formula computes detailed so the results close to each other but not same

[Jan]

@ferhat: Have you seen my comment to your question?

Answer 2

[Greg Heath]

It would be helpful if you gave up the formula.

Greg

[ferhat gecer]

it is very complex and i cant write it in this window. it has square roots,sum symbols..etc but you find it in Chapra's book (numerical analysis for engineers page 445) and the name of title is "quantification of error of linear regression"

[Greg Heath]

I'm retired and quite far from an accessible technical library.

Maybe someone else will take pity on me.

Greg