MULTIVARIABLE REGRESSION
MULTIVARIABLE REGRESSION
(OP)
I have a come across a problem involving 6 different variables and 2 outputs. How do i go about finding the coefficients for this data. Does anyone know how i can tackle this problem? I thank you in advance.





RE: MULTIVARIABLE REGRESSION
It would probably speed things no end if you were to post an example
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?
RE: MULTIVARIABLE REGRESSION
If it doesn't cover what you want to do could you give us more specifics.
Doug Jenkins
Interactive Design Services
http://newtonexcelbach.wordpress.com/
RE: MULTIVARIABLE REGRESSION
Katmar Software
Engineering & Risk Analysis Software
http://katmarsoftware.com
RE: MULTIVARIABLE REGRESSION
IDS:thank you for the info. i will look into it.
katmar: thanks for your suggestion.
Appreciate all for your replies.
Regards.
RE: MULTIVARIABLE REGRESSION
RE: MULTIVARIABLE REGRESSION
Katmar Software
Engineering & Risk Analysis Software
http://katmarsoftware.com
RE: MULTIVARIABLE REGRESSION
Looking at IVO=14, EVC=45, there are several examples when N, MAF and AFR are the same (e.g., there are 2 records with N=3000, MAF=300, AFR=14.3) but slightly different anwers for NOx, SDNMEP and TORQUE.
Just from simple examination of the data, the value of N (3000 vs 1000) seams to affect NOx (N decreases, NOx Decreases) and MAF affects TORQUE (MAF decrease, TORQUE decreases)
RE: MULTIVARIABLE REGRESSION
http://www.j-walk.com/ss/excel/tips/tip101.htm
thread770-184726: Excel Curve Fit Coefficients: Excel Curve Fit Coefficients
thread770-214997: Multivariable regression in Excell
RE: MULTIVARIABLE REGRESSION
I can get a pretty good linear regression model for torque as a function of 4 of the inputs. R-squared is 92.5% so I don't see a need to go to a polynomial.
For the SDNMEP, the linear model is based on the same 4 inputs, but the R-squared is 46%. May want to look at a quadratic or cube model here.
RE: MULTIVARIABLE REGRESSION
NOx SDNMEP TORQUE
Isn't NOx an output as well?
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?
RE: MULTIVARIABLE REGRESSION
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?
RE: MULTIVARIABLE REGRESSION
Now being downloaded (free for academic and non-commercial use it says).
Doug Jenkins
Interactive Design Services
http://newtonexcelbach.wordpress.com/
RE: MULTIVARIABLE REGRESSION
The Antaeus output looks impressive. I'm assuming that it's an interaction matrix. Will it also permit you to develop a regression equation?
Like I said, a linear model works fine if torque is an output.
For the SDNMEP, it's more complicated. I didn't bother to pursue it since I only assumed it was an output. It seems more logical to me to start with the inputs and finish with the outputs.
Maybe the newbee will clarify what are the inputs and what are the outputs. Or maybe this is homework!
RE: MULTIVARIABLE REGRESSION
katmar: the IVO, EVC,N,MAF,AFR and NOx are my independent variables. the other 2 are the dependent variables. the task is that i'll need to find out what form of equation is suitable for this data.
greg: y do you think say that NOx is an output?
THE PROBLEM I AM FACING IS THAT I DO NOT KNOW HOW TO CONVERT ALL THE INPUTS INTO A VECTOR ,SO THAT I COULD PLOT IT IN A GRAPH.CAN ANYONE SHOW ME HOW TO GO ABOUT IT?
I THANK U IN ADVANCE
RE: MULTIVARIABLE REGRESSION
RE: MULTIVARIABLE REGRESSION
Never the less, you've been given several sufficient links for a regression in Excel, and some comments indicating that a linear model may not suffice.
Short of doing your homework for you, I think you need to ask specific questions having actually tried to follow the advice thus far.
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?