In the context of multivariate statistical theory the paper offers a formula (or rather two formulae) for the distribution of the maximal or minimal eigenvalue of certain beta-dependent random matrices at any positive parameter beta. For beta equal to 1 the well known real-matrix distribution is reproduced, for beta equal to 2 and 4 its extension to complex and quaternionic matrix ensambles is obtained. The method is found in the Selberg-type integration of the eigenvalue densities leading to the hypergeometric functions of matrix argument. Remarkably related also to symmetric functions, Calogero-Sutherland models and Jack polynomials. Allowing, in addition, for an efficient numerical evaluation (cf. refs. [12. 13} by Koev et al) sampled by two Figures which demonstrate agreement with empirical data generated from 10000 samples at beta = 2 (complex matrices) and, in a terminating case, at a growing beta, respectively. MR2399565 Dumitriu, Ioana; Koev, Plamen Distributions of the extreme eigenvalues of beta-Jacobi random matrices. SIAM J. Matrix Anal. Appl. 30 (2008), no. 1, 1--6. 65F15 (15A52 33C70 60F05 62H10)