I have 3 vignettes mails in form of a picture.
Participants shall be randomly assigned to 3 treatment groups. Thus, each participant only gets to see 1 of the vignettes.
How can I do this?
For now, I created a page with the pretext and added the three different pics. What are the next steps?
Thank you so much for advice, you'll save my thesis!
PS: Deutsch oder English, beides ist fine ;)