Paper × 841 mm). A1 is half the size of a sheet of A0 (i.e., 594 mm × 841 mm), such that two sheets of A1 placed side by side are equal to one sheet of A0. A2 is half the size of a sheet of A1, and so forth. Common sizes used in the office and the home are A4 and A3 (A3 is the size of two A4 sheets). The density of paper ranges from for tissue paper to for some speciality paper. Printing paper is about . Paper may be classified into seven categories: Some paper types include:
Folded-t and half-t distributions Folded-t and half-t distributions In statistics, the folded-"t" and half-"t" distributions are derived from Student's "t"-distribution by taking the absolute values of variates. This is analogous to the folded-normal and the half-normal statistical distributions being derived from the normal distribution. The folded non-standardized "t" distribution is the distribution of the absolute value of the non-standardized "t" distribution with formula_1 degrees of freedom; its probability density function is given by: The half-"t" distribution results as the special case of formula_3, and the standardized version as the special case of formula_4. Folded-"t" and half-"t" generalize the folded normal and half-normal distributions by