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Table 1 Edinburgh Handedness Inventory data split by sample and sex

From: Prevalence and heritability of handedness in a Hong Kong Chinese twin and singleton sample

 ItemPreferenceTwinsSingletonsTotal
Itemtotal MaleFemaleχ2(df = 2)MaleFemaleχ2(df = 2)TwinsSingletonsχ2(df = 2)
 rClassN = 187N = 197 N = 220N = 204 N = 384N = 424 
  LH13 (7.0%)14 (7.1%) 16 (7.3%)9 (4.4%) 27 (7.0%)25 (5.9%) 
1. Writing.717NP4 (2.1%)0 (0.0%)4.263 (1.4%)5 (2.5%)2.174 (1.0%)8 (1.9%)1.37
  RH170 (90.9%)183 (92.9%) 201 (91.4%)190 (93.1%) 353 (91.9%)391 (92.2%) 
  LH15 (8.0%)13 (6.6%) 16 (7.3%)12 (5.9%) 28 (7.3%)28 (6.6%) 
2. Drawing.718NP11 (5.9%)8 (4.1%)1.0211 (5.0%)17 (8.3%)2.1419 (4.9%)28 (6.6%)1.11
  RH161 (86.1%)176 (89.3%) 193 (87.7%)175 (85.8%) 337 (87.8%)368 (86.8%) 
  LH16 (8.6%)20 (10.2%) 30 (13.6%)13 (6.4%) 36 (9.4%)43 (10.1%) 
3. Throwing.427NP65 (34.8%)69 (35.0%)0.3299 (45.0%)83 (40.7%)8.99*134 (34.9%)182 (42.9%)6.49*
  RH106 (56.7%)108 (54.8%) 91 (41.4%)108 (52.9%) 214 (55.7%)199 (46.9%) 
  LH16 (8.6%)12 (6.1%) 23 (10.5%)19 (9.3%) 28 (7.3%)42 (9.9%) 
4. Holding Scissors.659NP25 (13.4%)18 (9.1%)2.8643 (19.5%)20 (9.8%)8.57*43 (11.2%)63 (14.9%)4.66
  RH146 (78.1%)167 (84.8%) 154 (70.0%)165 (80.9%) 313 (81.5%)319 (75.2%) 
  LH16 (8.6%)12 (6.1%) 26 (11.8%)12 (5.9%) 28 (7.3%)38 (9.0%) 
5. Brushing Teeth.585NP44 (23.5%)49 (24.9%)0.8957 (25.9%)47 (23.0%)5.7593 (24.2%)104 (24.5%)0.81
  RH127 (67.9%)136 (69.0%) 137 (62.3%)145 (71.1%) 263 (68.5%)282 (66.5%) 
  LH11 (5.9%)14 (7.1%) 20 (9.1%)14 (6.9%) 25 (6.5%)34 (8.0%) 
6. Chopsticks.689NP8 (4.3%)2 (1.0%)4.199 (4.1%)8 (3.9%)0.7310 (2.6%)17 (4.0%)2.01
  RH168 (89.8%)181 (91.9%) 191 (86.8%)182 (89.2%) 349 (90.9%)373 (88.0%) 
  LH15 (8.4%)17 (9.0%) 20 (9.1%)12 (5.9%) 32 (8.7%)32 (7.5%) 
7. Spoon.559NP41 (23.0%)34 (18.1%)1.3857 (25.9%)66 (32.4%)3.1375 (20.5%)123 (29.0%)7.61*
  RH122 (68.5%)137 (72.9%) 143 (65.0%)126 (61.8%) 259 (70.8%)269 (63.4%) 
  LH17 (9.6%)18 (9.6%) 26 (11.9%)32 (15.8%)4.5335 (9.6%)58 (13.8%) 
8. Knife without fork.520NP24 (13.6%)14 (8.0%)3.0245 (20.5%)27 (13.4%) 39 (10.7%)72 (17.1%)11.57**
  RH136 (76.8%)155 (82.4%) 148 (67.6%)143 (70.8%) 291 (79.7%)291 (69.1%) 
  LH30 (16.9%)26 (13.9%) 40 (18.2%)30 (14.7%) 56 (15.3%)70 (16.5%) 
9. Broom.362NP49 (27.5%)42 (22.5%)2.4461 (27.7%)51 (25.0%)1.7991 (24.9%)112 (26.4%)0.57
(Upper hand) RH99 (55.6%)119 (63.6%) 119 (54.1%)123 (60.3%) 218 (59.7%)242 (57.1%) 
  LR11 (6.2%)20 (10.7%) 20 (9.1%)21 (10.3%) 31 (8.5%)41 (9.7%) 
10. Opening a box lid.410NP78 (43.8%)69 (36.9%)3.38116 (52.7%)95 (46.6%)1.61147 (40.3%)211 (49.8%)9.10*
  RH89 (50.0%)98 (52.4%) 84 (38.2%)88 (43.1%) 187 (51.2%)172 (40.6%) 
  1. 1) Q6 ‘chopsticks’ is a modified item to replace ‘striking a match’ in the original Edinburgh Handedness Inventory
  2. 2) For each task responses were recoded into three categories: ‘LH’, ‘NP’, and ‘RH’, in which LH = Left-handed. NP=No preference, and RH = Right-handed
  3. 3) Due to time constraint, 26 twin children and 2 singletons did not respond to the handedness questionnaire but participated in other tasks
  4. 4) Group difference for each item was compared by the 3 × 2 χ2 test and the significance was marked by * p < .05, and ** p < .005. p = .005 is the significant level after Bonferroni correction for 10 comparisons