| Interface | Mean Mental Workload | SE | df | lower.CL | upper.CL |
| Old | 4.86 | 0.1870 | 29 | 4.48 | 5.24 |
| UCD1 | 4.92 | 0.2011 | 29 | 4.51 | 5.33 |
| UCD2 | 4.44 | 0.1793 | 29 | 4.07 | 4.80 |