Less-than sign been repurposed for a range of uses and operations. The less-than sign (<) is an original ASCII character (hex 3C, decimal 60). The less-than sign is used for an approximation of the opening angle bracket (⟨). ASCII does not have angle brackets. In BASIC, Lisp-family languages, and C-family languages (including Java and C++), operator < means "less than". In Coldfusion, operator .lt. means "less than". In Fortran, operator .LT. means "less than"; later versions allow <. In Bourne shell, operator -lt means "less than". The double less-than sign («) is used for an approximation of the much-less-than sign (≪) or
Degrees of freedom (statistics) degrees of freedom. In some complicated settings, such as unbalanced split-plot designs, the sums-of-squares no longer have scaled chi-squared distributions. Comparison of sum-of-squares with degrees-of-freedom is no longer meaningful, and software may report certain fractional 'degrees of freedom' in these cases. Such numbers have no genuine degrees-of-freedom interpretation, but are simply providing an "approximate" chi-squared distribution for the corresponding sum-of-squares. The details of such approximations are beyond the scope of this page. Several commonly encountered statistical distributions (Student's t, Chi-Squared, F) have parameters that are commonly referred to as "degrees of freedom". This terminology simply reflects that in many applications