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Table 3 Relative estimation error by experimental condition, food (N = 3) and portion size (small, medium, large)

From: The international food unit: a new measurement aid that can improve portion size estimation

Condition

Food

Small portion

Medium portion

Large portion

F-test

  

Mdn

IQR

Mdn

IQR

Mdn

IQR

χ2 (2)

Measuring cup (N = 36)

Rice

33.7

49.5

38.4

57.7

42.8

71.4

3.72

Chicken

80.5a

90.3

116.6a,b

86.7

153.1b

81.4

14.39*

French fries

94.3a

103.6

129.3b

89.9

157.6b

87.1

11.17*

IFU™ (N = 31)

Rice

−23.9

38.0

−11.5

59.0

−17.8

36.5

0.84

Chicken

38.8

55.5

33.2

72.1

32.2

76.7

3.94

French fries

32.7

46.4

61.0

92.0

48.6

74.3

3.94

Modelling clay (N = 31)

Rice

1.4

81.1

6.3

73.8

18.7

80.4

5.10

Chicken

38.8

120.3

33.2

44.4

85.1

60.8

3.68

French fries

99.1

112.8

84.0

115.0

78.3

104.0

3.16

No aid (N = 30)

Rice

14.6

138.1

25.5

120.8

61.4

121.4

0.47

Chicken

95.9

170.1

107.5

176.6

135.4

117.7

0.47

French fries

38.3

145.2

48.8

120.0

55.0

145.2

1.67

  1. Note: Differences between several related groups were investigated using Friedman’s ANOVA with the Bonferroni correction for 12 comparisons (* P < .05). Post hoc comparisons were performed using the Wilcoxon signed-rank test with the Bonferroni correction for three comparisons. Different superscript letters indicate significant differences between groups