If there's a need to compare the strength of two or more different filaments that you have, then print these using the respective filaments, break them with your hands, and feel out the difference in strength to determine the right filament for your application! Make sure to use the same slicer settings for each plate you make to have the only difference be the filament type. This could be used with the same filament type but different brands or colors, such as a difference between Prusament PLA and Polymaker PLA or between a solid color PLA and multicolor silk PLA. (hint: if you're unable to break the plate with just your hands, then your filament is pretty strong!)