Table 2 Basic characteristics and mean differences of favored and un-favored foods scores in the two groups

Mean (SD) years of age

8.6 (2.4)

8.3 (1.8)

t = .76, df = 104, P = 0.4

Dosage of methylphenidate during the trial (mg/day)

12.7 (5.4)

11.9 (4.6)

t = .7, df = 83, P = 0.4

Dosage of methylphenidate before the trial (mg/day)

9.7 (7.2)

9.3 (2.9)

t = .3, df = 98, P = 0.7

Body mass index

16.1 (2.4)

15.4 (2.6)

t = 1.3, df = 102, P = 0.1

Inattentiveness score at baseline

15.7 (6.0)

15.8 (5.0)

t = .08, df = 104, P = 0.9

Inattentiveness score at the end

12.5 (5.3)

11.6 (5.8)

t = .7, df = 78, P = 0.4

Hyperactivity/impulsivity score at baseline

17.7 (6.0)

17.6 (5.1)

t = .03, df = 104, P = 0.9

Hyperactivity/impulsivity at end

13.9 (6.2)

13.1 (5.9)

t = .5, df = 78, P = 0.5

The mean difference of favorite diet during the trial

2.6 (3.9)

−.02 (1.9)

t = 3.7, df = 78, P < 0.0001

The mean difference of un-favorite diet during the trial

−6.5 (5.2)

−1.2 (3.7)

t = 5.2, df = 78, P < 0.0001

The mean difference of inattentiveness score during the trial

−3.3 (4.8)

−4.0 (5.1)

t = .7, df = 78, P = 0.4

The mean difference of hyperactivity/impulsivity score during the trial

−3.7 (4.7)

−5.0 (4.8)

t = 1.1, df = 78, P = 0.2