If you’ve already collected the data then one option is to copy and paste the data in that column to a text editor (I use PFE but Notepad should be fine). Then paste the data back to Excel in the new column. Sometimes (I’m not sure in this case) there’s an extra invisible character at the start of the number which makes it look like text.
Alternatively, an option within PsychoPy for future reference might be to add zero to the value, i.e. rating+0. That might force it to be seen as a number.
I can’t remember exactly what I’ve been doing when I’ve encountered this or what code was causing the issue.