Suppose if a tall plant (Tt) is cross breeded with a dwarf plant (tt). Then Their progeny will be Tt, Tt, tt, and tt.
So can we say that T is Dominant over t ?
Mendel Experiment Confusion
Yes, because the plant which is Tt is tall and not dwarf. It is because T is dominant over t, that tallness is expressed. If T was not dominant over t, then a hybrid Tt, would not be tall plant. You will not get a 3:1 ratio here, because the parent plants are not homozygous, but one is heterozygous.