Observational studies of exoplanet populations demonstrate that planet occurrence rates vary systematically and can be calculated based on stellar characteristics such as spectral type.
The claim states that stars of specific spectral types have a calculable probability of hosting planetary systems. Papers [0] and [4] explicitly compute occurrence rates and dependencies based on spectral types (e.g., M dwarfs, F, G, and K stars), supporting the notion that probabilities are calculable and vary by spectral class. The other papers discuss general planet formation, metallicities, or binaries without directly contradicting the calculability of occurrence rates by spectral type.