mography and a positive ultrasound test? When given this probability format, only 12.2% of our participants reached the correct solution (» 3/3). D. Massaro (1998) gave an example describing the same situation with frequencies': EFTA_R1_01521128 EFTA02444386 Wt..* I M./AU- I M•AU. ev1+8.t.l- M-11