It relates to probability density functions by explaining how the distribution of these averages or sums tends to approach a specific shape: the normal distribution (bell curve).

6.2 The Normal Distribution (pp. 220-231) You are not required to memorize the formula for the normal probability density function, but rather know the properties (symmetry and bell shape).

The formula for this distribution’s probability density function is shown below. Note that the only variable parameters are the mean and standard deviation.

Stefano Mazzuco, Bruno Scarpa, Fitting age-specific fertility rates by a flexible generalized skew normal probability density function, Journal of the Royal Statistical Society.

Application of Weibull distribution in a generalized way to estimate wind potential cannot always be advisable. The novelty of this work is to estimate wind potential using Normal probability density ...

Discover what a log-normal distribution is, its financial applications, and how to calculate it, including using Excel for ...

The first paper, “Risk estimation using the normal inverse Gaussian distribution”, by P. J. de Jongh and J. H. Venter, proposes practical methods for estimating a conditional normal inverse Gaussian ...