Statistics of Quadratic Response Surface

Description

Computes stationary point, 1st and 2nd principal axes of the quadratic response surface, shapes and curvatures along the congruence and incongruence lines, as well as various parameters useful for plot.siRSM.

Usage

1
2

Arguments

obj

an object of class siRSM, often the result of siRSM

b

coefficients of the response surface, e.g., obj$coef where obj is an object of class siRSM

xlim

x-boundaries in 3D (x,y,z)-perspective plot — used when surface.stats.main is called internally by plot.siRSM

ylim

y-boundaries in 3D (x,y,z)-perspective plot — used when surface.stats.main is called internally by plot.siRSM

Value

u0

x-coordinates of surface's stationary point

v0

y-coordinates of surface's stationary point

p10

intercept in xy-plane of surface's 1st principal axis

p11

slope in xy-plane of surface's 1st principal axis

p20

intercept in xy-plane of surface's 2nd principal axis

p21

slope in xy-plane of surface's 2nd principal axis

ax.congr

slope of surface along the congruence line, u-v=0

ax2.congr

curvature of surface along the congruence line, u-v=0

ax.incongr

slope of surface along the incongruence line, u+v=0

ax2.incongr

curvature of surface along the incongruence line, u+v=0

pl

intersection of 1st axis at lower border, to be used by plot.siRSM

ph

intersection of 1st axis at upper border, to be used by plot.siRSM

sl

intersection of 2nd axis at lower border, to be used by plot.siRSM

sh

intersection of 2nd axis at upper border, to be used by plot.siRSM

Author(s)

Huan Cheng, Mu Zhu

References

Edwards JR (2002), "Alternatives to difference scores: Polynomial regression analysis and response surface methodology," in Measuring and Analyzing Behavior in Organizations: Advances in Measurement and Data Analysis (F. Drasgow, N. Schmitt, Eds.), Jossey-Bass, pp. 350-400.