## 6 Evaluation Results
### Results of the Applied TRAM Model  
We initially examined the factor structure of the Greek version of the eight questionnaires that measure the variables included in the model based on TRAM. More specifically, we used confirmatory factor analyses to compare the a priori factor structures implied by previous theoretical and empirical research. In more detail:  
* Optimism questionnaire: The one-factor structure of the questionnaire based on 9 items (the optimism questionnaire that was administered in the present study included nine and not ten items as were the case with the original questionnaire) was not verified by the initial CFA. The results of the initial one-factor model were: Satorra-Bentler scaled \(\chi\)2 (27, N = 44) = 102.90, \(p\) = 0.00, CFI = 0.10, and RMSEA = 0.28 (CI90% 0.20 to 0.32). Consequently, a second CFA was performed, using a revised item set for the questionnaire. In the revised item set, according to the suggested modifications, as indicated by the Lagrange multiplier and Wald tests, and the largest standardized residuals as well, the one item (Item 10 of the original questionnaire) that failed to come up with a one-factor solution corresponding to the optimism questionnaire, was dropped. Using the revised item set, the model yielded a noticeably better fit to data compared to the initial model: Satorra-Bentler scaled \(\chi\)2 (17, N = 44) = 20.88, \(p\) = 0.40, CFI = 0.99, and RMSEA = 0.02 (CI90% 0.00 to 0.15). Thus, we concluded that the variance of that one factor could be explained by the users' optimism regarding the biofeedback system under study. * Innovativeness questionnaire: The one-factor structure of the questionnaire based on 7 items was not confirmed by the initial CFA. The results of the initial one-factor model were: Satorra-Bentler scaled \(\chi\)2 (15, N = 44) = 88.05, \(p\) = 0.00, CFI = 0.13, and RMSEA = 0.35 (CI90% 0.27 to 0.41). Consequently, a second CFA was performed, using a revised item set for the questionnaire. In the revised item set, according to the suggested modifications, as indicated by the Lagrange multiplier and Wald tests, and the largest standardized residuals as well, two items (Items 4 and 6 of the original questionnaire) that failed to come up with a one-factor solution corresponding to the innovativeness questionnaire, were dropped. Using the revised item set, the model yielded a better fit to data compared to the initial model: Satorra-Bentler scaled \(\chi\)2(4, N = 44) = 1.57, \(p\) = 0.70, CFI = 1.00, and RMSEA = 0.00 (CI90% 0.00 to 0.15). Thus, we derived one factor, which could be explained by the users' innovative attitude towards the system under study. * Insecurity questionnaire: The one-factor structure of the questionnaire based on nine items was not confirmed by the initial CFA. The results of the initial one-factor model were: [PERSON] scaled \(\chi\)2 (27, N = 44) = 112.32, \(p\) = 0.00, CFI = 0.44, and RMSEA = 0.35 (CI90% 0.24 to 0.35). Consequently, a second CFA was performed, using a revised item set for the questionnaire. In the revised item set, according to the suggested modifications, as indicated by the Lagrange multiplier and Wald tests, and the largest standardized residuals as well, four items (Items 1, 2, 5 and 8 of the original questionnaire) that failed to come up with a one-factor solution corresponding to the insecurity questionnaire, were dropped. Using the revised item set, the model yielded a better fit to data compared to the initial model: [PERSON] scaled \(\chi\)2 (3, N = 44) = 1.10, \(p\) = 0.47, CFI = 1.00, and RMSEA = 0.00 (CI90% 0.00 to 0.25). Thus, we derived one factor, which could be explained by the users' insecurity regarding the biofeedback system under study. * Discomfort questionnaire: The one-factor structure of the questionnaire based on 10 items was not confirmed by the initial CFA. The results of the initial one-factor model were: Satorra-Bentler scaled \(\chi\)2 (35, N = 44) = 265.20, \(p\) = 0.00, CFI = 0.29, and RMSEA = 0.43 (CI90% 0.35 to 0.44).