generates_transformation_functions_Tb {MTSYS} | R Documentation |
Function to generate data transformation functions for the Tb methods
Description
generates_transformation_functions_Tb
is the argument for the
parameter generates_transform_functions
in genera_T
, which
is used in the Tb method.
Usage
generates_transformation_functions_Tb(sample_data)
Arguments
sample_data |
Matrix with n rows (samples) and (p + 1) columns (variables). The Tb method uses all data to generate the unit space. All data should be continuous values and should not have missing values. |
Value
generates_transformation_functions_Tb
returns a list
containing three functions. For the first component, the data
transformation function for independent variables is a function
that subtracts the center of each independent variable. The center
is determined in a specific manner for the Tb method. The center
consists of each sample value which maximizes the signal-to-noise
ratio (S/N) per independent variable. The values are determined
independently so that different samples may be selected for
different variables. For the second component, the data
transformation function for a dependent variable is a function that
subtracts the dependent variable of the sample which maximizes the
S/N per independent variable. For the third component, the inverse
function of the data transformation function for a dependent
variable is a function that adds the weighted mean of a dependent
variable. The weighted mean is calculated based on the S/N and the
frequency of being selected in independent variables.
References
Inou, A., Nagata, Y., Horita, K., & Mori, A. (2012). Prediciton Accuracies of Improved Taguchi's T Methods Compared to those of Multiple Regresssion Analysis. Journal of the Japanese Society for Quality Control, 42(2), 103-115. (In Japanese)
Kawada, H., & Nagata, Y. (2015). An application of a generalized inverse regression estimator to Taguchi's T-Method. Total Quality Science, 1(1), 12-21.
See Also
Examples
# The value of the dependent variable of the following samples mediates
# in the stackloss dataset.
stackloss_center <- stackloss[c(9, 10, 11, 20, 21), ]
tmp <- generates_transformation_functions_Tb(stackloss_center)
center_subtraction_function <- tmp[[1]]
subtracts_ys <- tmp[[2]]
adds_M_0 <- tmp[[3]]
is.function(center_subtraction_function) # TRUE
is.function(subtracts_ys) # TRUE
is.function(adds_M_0) # TRUE