A farmer grows crops with an average height of 5 feet. He breeds his tallest plants, which are 8 feet tall. They produce offspring that have an average height of 5.25 feet. So the heritability in this case is

Breeder's equation:

R = h²*S

The Response to Selection (R) is defined as the realized average difference between the parent generation and the next generation 5-5.25 = - 0.25

and the Selection Differential (S) is defined as the average difference between the parent generation and the selected parents 5-8 = - 3

h² = R/S = (-0.25) / (-3) = 0.08

heritability h = √0.08 = 0.29