So these are the two possibilities. If it's this, then we'll get these offspring. But if it's this, we'll get this distribution of our offspring. So let's suppose I take the test. I conduct this experiment, let's say 1000 times. Now, if I conducted 1000 times and about 500 of the offspring are tall and 500 of the offspring are short, then I know that the genotype of my initial plant was in fact heterozygous, because only a heterozygous genotype will produce the short offspring will never see short offspring in this distribution.