Editing Normal distribution (section)

=== Approximate normality ===
''Approximately'' normal distributions occur in many situations, as explained by the [[central limit theorem]]. When the outcome is produced by many small effects acting ''additively and independently'', its distribution will be close to normal. The normal approximation will not be valid if the effects act multiplicatively (instead of additively), or if there is a single external influence that has a considerably larger magnitude than the rest of the effects.
* In counting problems, where the central limit theorem includes a discrete-to-continuum approximation and where [[infinitely divisible]] and [[Indecomposable distribution|decomposable]] distributions are involved, such as
** [[binomial distribution|Binomial random variables]], associated with binary response variables;
** [[Poisson random variables]], associated with rare events;
* [[Thermal radiation]] has a [[Bose–Einstein statistics|Bose–Einstein]] distribution on very short time scales, and a normal distribution on longer timescales due to the central limit theorem.