Figure 7.

Clustering results according to the variables evaluated from video records of volunteers while executing exercise 3. (a) Clustering classification using variables: T_Span, Total_Task1, and T_Ratio. Errors were not utilized in this classification process, to evaluate if it introduces subjective bias (Estimating the number of errors is dependent on the judgment of the evaluator); (b) Hierarchical classification using variables: variables T_Span, Total_Task1, T_Ratio, and Errors. Three groups can be clearly differentiated, blue (volunteers 1, 4, 5, 9, 12 and 13), red (volunteers 7, 8, 11 and 14) and green (volunteers 2, 3, 6 and 10); volunteer 10 can be considered either green or red.