Probability distribution functions (PDFs) describe the expected values of random variables drawn from a sample. The shape of the PDF explains how likely it is that an observed value might occur.

By using one of the common stock probability distribution methods of statistical calculations, an investor may determine the likelihood of profits from a holding.

This paper examines the question of how strongly the skewness of the daily temperature variable (t) affects estimating the mean value and variance of the corresponding degree day variable (q) at U.S.