Statistical evaluation was conducted using SPSS for Windows, Version 22.0 (SPSS Inc., NY, U.S.A.) and BiAS. for Windows, Version 10.12. (epsilon-Verlag GbR, Hochheim Darmstadt, Germany). The sample size (200 participants) was calculated with an expected standard deviation of four score points, minimal different score point delta between 1.6 and 2, p-value of 0.05 and a power of 0.8 [24]. The categorised data was evaluated based on the Chi-squared test (question 2-6, 8-12, 15, 16), the precise test according to Fisher (question 1, 7, 13, 14). A two-sided review of significance was applied to each of the tests, whereby a p-value of <0.05 was assumed to be statistically significant for all statistical tests.