## 3 Results
These results indicate that students experienced the interaction with the robotic facilitator not only as interesting and exciting but also as helpful for understanding planning poker and gaining confidence in agile estimation. However, some results also indicate that the design of the interaction with the robot could be further improved, especially when it comes to enhancing motivation (item 24, M = 3.63) and overcoming the novelty effect (item 28, M = 3.33). The analysis of the qualitative data from the open question, \"What are your recommendations for improving the planning poker in a team with a robot facilitator like [PERSON]? Please share your thoughts and ideas!\" revealed some further important directions for improvement in the design of human-robot interaction. Although many participants confirmed that they fully enjoyed interacting with [PERSON] (e.g., \"It was really fun\" or \"I had a lot of fun\"), some students criticised lengthy information chunks provided by the robot (e.g., \"At some points he talks for too long\" or \"Make it short and clear\"), and issues related to speech recognition (e.g.,\"Other than the speech recognition the experience was actually really pleasant!\" or \"Use a better voice detector\"). Some students also wished for more interaction with [PERSON] for the enhancement of collaboration in the group, e.g., \"More interaction and evaluation tips from NAO\". RQ3: To What Extent Did the Previous Experience with the NAO Robot Influence the Quality of the Robot-Supported Collaborative Experience? In order to answer the third question, descriptive statistics were computed for previous experience with NAO, which was a nominal variable with two categories: yes/no. Out of 46 respondents, 19 participants (41%) reported having previous experience with NAO, while 27 participants (59%) reported having no previous experience. Next, the Shapiro-Wilk test was used to assess the normality of data distribution in the shortened learning experience scale and in the NAO interaction experience scale. Since dependent variables were not normally distributed, Mann-Whitney U Test was used as a non-parametric alternative to ANOVA. The results of the Mann-Whitney U Test showed that there were only two significant differences between the two groups, i.e., students \"with prior experience with NAO\" and students \"without prior experience with NAO\". The first statistically significant difference was related to the level of confidence in agile estimation (item 27 \"I feel confident in agile estimation after playing planning poker with NAO\"), which was statistically significantly higher among students without prior experience with NAO com \begin{table}
\begin{tabular}{l l l} \hline \hline
**Item** & **Mean** & **Std. Deviation** \\ \hline
23. The interaction with [PERSON] during planning poker was exciting. & 4.04 & 0.842 \\ \hline
24. The interaction with [PERSON] during planning poker was motivating. & 3.63 & 1.123 \\ \hline
25. The interaction with [PERSON] during planning poker was frustrating. * & 1.87 & 1.108 \\ \hline
26. The interaction with [PERSON] was disappointing. * & 1.83 & 1.039 \\ \hline
27. I feel confident in agile estimation after playing planning poker with NAO. & 4.13 & 0.653 \\ \hline
28. I would like to play planning poker with [PERSON] again. & 3.33 & 1.076 \\ \hline \hline \end{tabular}
* Negatively formulated items.  
\end{table} 
Table 4: _Cont._pared with students with prior experience (U = 172, \(p\) = 0.035). The comparison of means showed that students \"without prior experience with NAO\" (n 27) felt more confident (M = 4.30) compared with students \"with prior experience with NAO\" (n 19, M = 3.89). The second statistically significant difference between the two groups was related to item 4 \"I felt bored while playing planning poker in a team\", which was statistically significantly higher among students with prior experience with NAO compared with students without prior experience (U = 173, \(p\) = 0.047).