Variable Transformations |
Figure 32.13 shows the transformations that are available when you select Variance stabilizing from the Family list. Variance stabilizing transformations are often used to transform a variable whose variance depends on the value of the variable. For example, the variability of a variable might increase as
increases. Equations for these transformations are given in Table 32.3.
![]() |
Figure 32.13: Variance Stabilizing Transformations
Default | Name of | ||
---|---|---|---|
Transformation | Parameter | New Variable | Equation |
log(Y+a) | ![]() |
Log_Y | ![]() |
log10(Y+a) | ![]() |
Log10_Y | ![]() |
sqrt(Y+a) | ![]() |
Sqrt_Y | ![]() |
1 / Y | Inv_Y | ![]() |
|
arcsinh(Y) | Arcsinh_Y | ![]() |
|
generalized log(Y;a) | ![]() |
GLog_Y | ![]() |
log-linear hybrid(Y;a) | ![]() |
LogLin_Y | See text. |
The log-linear hybrid transformation is defined for as follows:
The generalized log and the log-linear hybrid transformations were introduced in the context of gene-expression microarray data by Rocke and Durbin (2003).
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