*6.2. Darwin's Plant Fertilization Data*

Darwin [29] performed an experiment to determine whether self-fertilized plants and cross-fertilized plants have different growth rates. He sowed in pots pairs of *Zea mays* plants, one self-fertilized and the other cross-fertilized, and after a specific time period, the height of each plant was measured. A particular sample of *n* = 15 pairs of plants led to the following paired differences (cross-fertilized minus self-fertilized).
