# How can I write the response surface methodology (RSM) equation from coefficients including block effect?

I fitted a model by rsm function in R, and here is the code:

rsm1 = rsm(x ~Block+FO(x1,x2,x3)+PQ(x1,x2,x3), data=t1.df)


The coefficients, obtained from the rsm1\$coefficients function are:

(Intercept) = 0.990627264,
Block2 = -0.069201060,
FO(x1, x2, x3)x1 = 0.096171838 ,
FO(x1, x2, x3)x2 = 0.006456881,
FO(x1, x2, x3)x3,  -0.011316078,
PQ(x1, x2, x3)x1^2 = -0.050611735,
PQ(x1, x2, x3)x2^2 =  -0.044424551,
PQ(x1, x2, x3)x3^2 = -0.047076201


Then, RSM equation can be written like this:

y = 0.990627264 + (-0.069201060)Block + 0.096171838.x1 + 0.006456881.x2 - 0.011316078. x3 - 0.050611735.x1^2 - 0.044424551.x2^2 - 0.047076201.x3^2


How do I write the "Block" using x1, x2, x3......

• The equation you show is correct for block 1. To get the equation for block 2, subtract .06920160 from the intercept. – Russ Lenth Jul 10 at 4:11