I am conducting an experiment with two independent variables a) the robot modality with 3 levels (face, voice, language) and emotion expression (happy, angry, neutral), thus resulting in a total of 9 groups :
1. happy_face
2.neutral_face
3. angry_face
4. happy_voice
5. neutral_voice
6. angry_voice
7. happy_text
8. neutral_text
9. angry_text
Each modality involves different media files, for instance, face= video, voice= audio file, and language= text file, which will be presented in either happy, angry, or neutral conditions. How I can create a random generator where participants will be randomly assigned into each group with different media files? A response would be very much appreciated. Thank you in advance.