# Normal frequency distribution

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A normal frequency distribution is a theoretical continuous, symmetrical, bell-shaped distribution function. Its mean, mode and median are all the same; and both the tails of the bell curve are infinitely long.

Because of its symmetry, a normal frequency distribution can be described fully by its mean and its standard deviation.

Commonly abbreviated to *normal distribution*.

Simple normal distributions are frequently used for modelling uncertainty. However, reality is rarely so neat and symmetrical as the normal distribution model.

This can lead to spurious accuracy and a false sense of security from relying on models of that kind.

## See also

- Binomial
- Distribution
- Fat tail
- Frequency distribution
- Kurtosis
- Leptokurtic frequency distribution
- Lognormal frequency distribution
- Mean
- Mode
- Median
- Skewness
- Standard deviation
- Standardised normal distribution
- Tail event
- Tail risk
- Value at risk