Multiple regression with 2 categorical variables

Xtina · Jul 31, 2012

Hi all! I would like to know how to obtain a regression model to make predictions about the value of a dependant variable if the independent variables are categorical.I read about transforming them into Dummy variables, but I don't know how to do it in Statgraphics. I would like to estimate the Young's modulus of concrete elements from the type of dosage (D1, D2, D3 and D4) and the type of aggregates (A1, A2, A3, A4, A5), but i only have the experimental results from:

D1-A3
D1-A5
D1-A2
D2-A4
D2-A5
D2-A3
D3-A2
D4-A1
D4-A2

It is not a complete design of experiments... ¿is there any solution? Thanks in advance...

GregLocock · Jul 31, 2012

Of course there is /a/ solution, the question is, is it a good one?

without seeing the actual data it is hard to say what model is appropriate. You might build a simple model using say a3.d1 and a3.d2 to look at the strength of d1 to d2, and so on.

Cheers

Greg Locock

New here? Try reading these, they might help FAQ731-376

http://eng-tips.com/market.cfm?

IRstuff · Jul 31, 2012

If nothing else, you ought to at least be able to put everything into a surface plot.

TTFN
faq731-376

Eng-Tips is the largest engineering community on the Internet

Intelligent Work Forums for Engineering Professionals

Multiple regression with 2 categorical variables

Xtina

Civil/Environmental

Recommended for you

GregLocock

Automotive

IRstuff

Aerospace

Similar threads

Part and Inventory Search

Sponsor