Log absolute value stabilization of a normal scale family

ID: log-absolute-value-stabilization-of-a-normal-scale-family

For with and fixed , represent with having the standard normal distribution. Taking the natural logarithm of the absolute value gives the displayed identity. Its random second term has a common distribution, independent of , so this variance-stabilizing transformation gives an exactly constant variance. That variance is finite: the normal density is bounded near zero and , while normal tails control logarithmic growth at infinity. The transformation is defined almost surely, loses the sign of the mean, and does not produce an exact normal distribution. A zero mean makes the original observation identically zero and is outside its domain.

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