Chromosome number provides no reference for establishing any relationship between organisms. The number of chromosome cannot depict whether a living species belong to plant kingdom or animal kingdom. It cannot even depict the evolutionary history of any species. Thus, the organism with lesser chromosome has not necessarily evolved from the species having larger number of chromosome or vice versa.
Chromosome number can only depict the quantity of genetic material with in an organism and hence no relationship can be established living species only on the basis of chromosome number.
A pretest/posttest experiment is an experiment that includes double measurements at multiple points in time. In this kind of test, measurements (measurement of dependent variable) are taken both before and after a treatment.
