D.5.1 As pointed out in the Guide, the t-distribution is often tabulated in quantiles. That is, values of the quantile t_{1-α} are given, where 1 - α denotes the cumulative probability and the relation $$1 - \alpha = \int_{-\infty}^{t_{1-\alpha}} f(t,\nu) {\rm d}t $$ defines the quantile, where f is the probability density function of t. Thus t_{p} of this Technical Note and of the Guide and t_{1-α} are related by p = 1 - 2α. For example, the value of the quantile t_{0.975}, for which 1 - α = 0.975 and α = 0.025, is the same as t_{p}(ν) for p = 0.95, It should be noted, however, that in reference [D.2] the symbol p is used for the cumulative probability 1 - α, and the resulting t_{p}(ν) is called the "quantile of order p of the t variable with ν degrees of freedom." Clearly, the values of t_{p}(ν) defined in this way differ from the values of t_{p}(ν) defined as in this Technical Note and in the Guide, and given in Table B.1 (which is of the same form as that given in reference [10]). Thus, one must use tables of tabulated values of t_{p}(ν) with some care.