Data Transformations

The programs accessed on this page are aimed at systematically transforming a skewed distribution into one that more closely approximates the symmetrical form of a normal distribution. A separate page, entitled Computational Details, describes how these several types of transformations are accomplished.

Procedure:

Raw Data
Transformed Data







For data with positive skewQ
» square root:Q
» natural logarithm:Q
» inverse (1/X):Q

For data with negative skewQ
» square root (reflected):Q
» natural logarithm (reflected):Q
» Inverse (1/X) (reflected):Q


Computational Details


Proportions in Distribution
beyond
-2sd

-1sd to
-2sd

mean to
-1sd

mean to
+1sd

+1sd to
+2sd

beyond
+2sd

TTNormal
0.0228
0.1359
0.3413
0.3413
0.1359
0.0228
Raw






Transformed






sd = standard deviation




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