“…We also provide the first known examples of absolutely simple abelian varieties A over Q having dimension greater than one for which the average rank of A s (Q) is bounded, and indeed we give such examples over any number field F and in arbitrarily large dimension. 1 The proofs of these results are accomplished through a computation of the average size of a family of Selmer groups, namely, the φ-Selmer groups associated to a quadratic twist family of 3-isogenies φ s : A s → A ′ s of abelian varieties. There have been a number of recent results on the average sizes of Selmer groups in large universal families of elliptic curves or Jacobians of higher genus curves (see, e.g., [2,3,5,6,39,40,44]) obtained via geometry-of-numbers methods.…”