Statistics for An investigation into the effect of seasonal root replacement upon plant longevity in perennial ryegrass (Lolium Perenne), Italian ryegrass (L. multiflorum), tall fescue (Festuca arundinacea) and annual meadow grass (Poa annua) : a thesis presented at Massey Agricultural College in part fulfillment of the requirements for the degree of Master of Agricultural Science in the University of New Zealand