welding {statmod}R Documentation

Data: Tensile Strength of Welds


This is a highly fractionated two-level factorial design employed as a screening design in an off-line welding experiment performed by the National Railway Corporation of Japan. There were 16 runs and 9 experimental factors. The response variable is the observed tensile strength of the weld, one of several quality characteristics measured. All other variables are at plus and minus levels.




A data frame containing the following variables. All the explanatory variables are numeric with two levels, -1 and 1.
Variable Description
Rods Kind of welding rods
Drying Period of drying
Material Welded material
Thickness Thickness
Angle Angle
Opening Opening
Current Current
Method Welding method
Preheating Preheating
Strength Tensile strength of the weld in kg/mm. The response variable.




Smyth, G. K., Huele, F., and Verbyla, A. P. (2001). Exact and approximate REML for heteroscedastic regression. Statistical Modelling 1, 161-175.

Smyth, G. K. (2002). An efficient algorithm for REML in heteroscedastic regression. Journal of Computational and Graphical Statistics 11, 1-12.

[Package statmod version 1.2.4 Index]