Using a data sheet, the physicians answered the
question, Can you definitely see a blue color? (same as
experiment 1). The physicians were not instructed how
many samples, if any, would be positive. None of these
physicians participated in experiment 1, so they were
highly unlikely to have seen a positive Meixner reaction
recently. Each observer was shown the papers without any
input from the other observers. The number of emergency
physicians (5) and the number of different amounts of
each substance (2) resulted in a total of 10 readings for
each substance.