## 3 Results  
### Weighted Mean Absolute Error  
#### 3.1.1 Aggregated Results  
The data analysis exposed a wMAE of \(18.80^{\circ}\pm 12.12^{\circ}\) degrees for all angles in the whole data set. The wMAE across all exercises, views, and angles is visualized in Figure 4 to enable more profound insights into the performance based on exercises and joint angles.  
The data exposed high differences in the detected error rates with the wMAE ranging between \(3.75^{\circ}\pm 0.99^{\circ}\) (Lateral Arm Raise, Left Elbow, Side) and \(47.06^{\circ}\pm 5.11^{\circ}\) (Side Squat, Left Elbow, Side), depending on the performed exercise and observed joint. To generate better insights into the different factors, we aggregated the wMAE by angle, performed exercise, view, and subject.  
Considering the aggregated wMAE for the individual joints (Table 1), the mean value ranged between \(16.61^{\circ}\pm 7.47^{\circ}\) for the left knee up to \(24.00^{\circ}\pm 17.43^{\circ}\) for the left elbow. The left hip exposed a wMAE of \(16.91^{\circ}\pm 10.67^{\circ}\), followed by the right shoulder with a wMAE of \(17.39^{\circ}\pm 12.18^{\circ}\) and the right knee with a value of \(17.57^{\circ}\pm 7.25^{\circ}\). The right elbow had a wMAE of \(20.00^{\circ}\pm 15.32^{\circ}\), the left shoulder \(20.01^{\circ}\pm 14.89^{\circ}\) and the right hip \(20.17^{\circ}\pm 11.25^{\circ}\).  
The observed wMAE differed between the exercises, with the Lateral Arm Raise (\(9.56^{\circ}\pm 6.13^{\circ}\)), Jumping Jacks (\(10.09^{\circ}\pm 3.81^{\circ}\)), Single Leg Deadlift (\(11.35^{\circ}\pm 5.04^{\circ}\)), Reverse Fly (\(15.80^{\circ}\pm 8.5^{\circ}\)), Leg Extension Crunch (\(18.15^{\circ}\pm 8.21^{\circ}\)), and Front Lunge (\(18.19^{\circ}\pm 8.98^{\circ}\)) exposing significantly lower error rates than the Side Squat (\(30.49^{\circ}\pm 12.73^{\circ}\)) and the Squat (\(33.79^{\circ}\pm 10.25^{\circ}\)) (Table 2).  
When only considering the targeted joints, the wMAE ranged between \(3.75^{\circ}\pm 0.99^{\circ}\) (Lateral Arm Raise, Left Elbow, Side View) and \(38.41^{\circ}\pm 6.66^{\circ}\) (Squat, Right Hip, Frontal View). The exercises Lateral Arm Raise, Reverse Fly, and Single Leg Deadlift performed best with wMAE values below \(15.00^{\circ}\) in the relevant joints for the respective exercises. The wMAE of Jumping Jacks, Front Lunge, and Leg Extension Crunch remained below \(25.00^{\circ}\) across the targeted joints. The Squat and Side Squat Exercises exposed error rates of up to \(38.41^{\circ}\) in the targeted joints and thus performed worst in the experiment.  
When only considering the targeted joints per exercise, the wMAE was reduced for all exercises except the Jumping Jacks, where the wMAE remained the same (Table 2).  
The difference between the view of the recording device was smaller than the observed differences between the exercises, with an wMAE of \(17.91^{\circ}\pm 9.68^{\circ}\) for the side view and \(19.35^{\circ}\pm 13.38^{\circ}\) for the frontal view.  
When considering the different subjects, the observed wMAE was relatively consistent among the individuals, with mean values ranging from \(16.20^{\circ}\pm 9.44^{\circ}\) to \(22.32^{\circ}\pm 17.08^{\circ}\).