Interaction and sample size required for Capron and Duyme balanced fostering study of IQ : a reply to Wahlsten. Reply to reply

Wahlsten (1993) calculated the sample size required for a psychologically interesting interaction for Full IQ. He used partial data from our adoption study as a guide and suggested that a transnational study of sufficient sample size could be conducted to test for the existence of an interaction. Some of his results need clarification so the reader can avoid confusing the hypotheses with empirical data.