Fig. 1

Bland–Altman plot of the differences between test 1 and 2 (retest) for the total score of the Health Questionnaire on Back Care and Spine Disease Prevention for 6–10 Years Old Children. The observed mean of agreement (solid lines) and limits of agreement (dashed lines) are presented within ±2 standard deviations (n = 463). x-axis: Mean of the total scores of the Health Questionnaire on Back Care and Spine Disease Prevention Knowledge for 6–10 years old children between test 1 and 2; y-axis: Differences of the total scores of the Health Questionnaire on Back Care and Spine Disease Prevention Knowledge for 6–10 years old children between test 1 and 2. ______observed average agreement, __________95% limit of agreement