A dataframe containing 3 columns (d, y1 and y2) and 712 rows.
d is a numeric vector specifying the gold-standard results (1 = presence of disease, 0 = absence of disease).
y1 is a numeric vector specifying the results of diagnostic test 1 (1 = positive, 0 = negative).
y2 is a numeric vector specifying the results of diagnostic test 1 (1 = positive, 0 = negative).