Dataplot

• Question:

  What is best Box-Cox transformation T(.) of Y so that

      T(Y) versus X is homoscedastic (= constant variance)

• Definition:

  NOTE: This plot is still under development.

  Vertical Axis : ....

      where T(Y) is the Box-Cox transformation of Y

  Horizontal Axis: Box-Cox power transformation parameter (lambda)

• Interpretation/Conclusion:

  Best transformation is lambda = 0.5 (i.e., square root)

• NIST/SEMATECH Handbook Chapter:

  1. Process/Product Exploration

  2. Process/Product Modeling

• Reference:

  Filliben

Dataplot Code:

SKIP 25

READ BERGER1.DAT Y X

LET X2 = 5*INTEGER(X/5)

BOX-COX HOMOSCEDASTICITY PLOT Y X2

Dataplot Reference Manual Documentation
for BOX-COX HOMOSCEDASTICITY PLOT (requires Adobe Acrobat Reader)