Effect of dynamical state of clusters on the coefficients of a linear relation between the normalised line of sight velocity dispersion, σ_los/V_c, and the apparent elongation, q_2D, inferred from the galaxy distribution on the sky. The red contours, with (σ_los/V_c)(q_2D = 0.7) ≳ 0.625, show constraints for dynamically old clusters and the blue ones, with (σ_los/V_c)(q_2D = 0.7) ≲ 0.625, for dynamically young. The filled and empty contours correspond to the clusters selected by the fraction of red galaxies and by the magnitude gap of the two brightest galaxies, respectively. The contours show the 68 and 95 per cent confidence regions of the posterior probability distribution marginalised over the intrinsic scatter in σ_los/V_c. Clusters at different dynamical states exhibit consistently a correlation between the normalised line of sight dispersion and the apparent elongation.