(a) Observed visual luminosity–to–mass ratio vs. age for five clusters (crosses) compared with Starburst99 models with different IMF parameters (curves) as shown in Fig. 15. (b) Zoomed version of the insert in (a) showing only NGC 330 and M82‐F. The solid curve corresponds to the solid curve in (a). The three curves above the solid curve are for Starburst99 models with nonconservative cluster mass and solar metallicity.