Applying the Concepts and SkillsFoot-pressure Angle. Genu valgum, commonly known as “knee-knock,” is a condition in which the knees angle in and touch one another when standing. Genu varum, commonly known as “bowlegged,” is a condition in which the knees angle out and the legs bow when standing. In the article “Frontal Plane Knee Angle Affects Dynamic Postural Control Strategy during Unilateral Stance” (Medicine and Science in Sports&Exercise, Vol. 34, No. 7, pp. 1150–1157), J. Nyland et al. studied patients with and without these conditions. One aspect of the study was to see whether patients with genu valgum or genu varum had a different angle of foot pressure when standing. The following table provides summary statistics for the angle, in degrees, of anterior-posterior center of foot pressure for patients that have genu valgum, genu varum, or neither condition. Condition nj xj sj Genu varum 11 60.6 8 Genu valgum 16 40.7 7 Neither 29 54.2 6 At the 1% significance level, do the data provide sufficient evidence to conclude that a difference exists in the mean angle of anteriorposterior center of foot pressure among people in the three condition groups? Note: For the degrees of freedom in this exercise: a 0.1 0.05 0.025 0.01 0.005 Fa 2.41 3.17 3.96 5.03 5.87
Applying the Concepts and Skills
Foot-pressure Angle. Genu valgum, commonly known as “knee-knock,” is a condition in which the knees angle in and touch one another when standing. Genu varum, commonly known as “bowlegged,” is a condition in which the knees angle out and the legs bow when standing. In the article “Frontal Plane Knee Angle Affects Dynamic Postural Control Strategy during Unilateral Stance” (Medicine and Science in Sports&Exercise, Vol. 34, No. 7, pp. 1150–1157), J. Nyland et al. studied patients with and without these conditions. One aspect of the study was to see whether patients with genu valgum or genu varum had a different angle of foot pressure when standing. The following table provides summary statistics for the angle, in degrees, of anterior-posterior center of foot pressure for patients that have genu valgum, genu varum, or neither condition.
| Condition | nj | xj | sj |
| Genu varum | 11 | 60.6 | 8 |
| Genu valgum | 16 | 40.7 | 7 |
| Neither | 29 | 54.2 | 6 |
At the 1% significance level, do the data provide sufficient evidence to conclude that a difference exists in the mean angle of anteriorposterior center of foot pressure among people in the three condition groups? Note: For the degrees of freedom in this exercise:
| a | 0.1 | 0.05 | 0.025 | 0.01 | 0.005 |
| Fa | 2.41 | 3.17 | 3.96 | 5.03 | 5.87 |
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