Size parameter in bubble chart

Hi Team,

I want to use columns as dropdown in slicer and then use that filter in size parameter in bubble chart. So i would like to know:

1. How to make such dropdown i.e. which has columns as an option?

2. Is it possible to use such dropdown in size parameter in bubble chart, and if yes, how?

Thanks in advance,

Regards,

Ali Asgar Zakir