Table 3 Numbers of correct solutions of positive predictive values*

Frequency tree

(n = 94)

2 × 2 table

(n = 90)

Frequency tree

(n = 74)

2 × 2 table

(n = 75)

0–1

(0–1 answer correct)

19(20)

18(20)

53 (72)

50 (67)

2–3

(2–3 answers correct)

20 (21)

20 (22)

2 (3)

5 (7)

4–5

(4–5 answers correct)

55 (59)

52(58)

19 (26)

20(27)