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Testing differences in relative growth rate: A method avoiding curve fitting and pairing
Author(s) -
Poorter Hendrik,
Lewis Charles
Publication year - 1986
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1986.tb02447.x
Subject(s) - pairing , variance (accounting) , mathematics , growth rate , growth curve (statistics) , polynomial , statistics , variable (mathematics) , relative growth rate , orthogonal polynomials , order (exchange) , mathematical analysis , geometry , physics , superconductivity , accounting , finance , quantum mechanics , economics , business
A method is discussed to test differences in relative growth rates. This method is based on an analysis of variance, with In‐transformed plant weight as dependent variable. A significant Group × Time interaction indicates differences in relative growth rates between groups. The advantages over the “classical” and “functional” growth analyses are: (1) No pairing procedure is required. (2) More than two groups may be evaluated in one analysis. (3) No decision is required about the polynomial used to fit the data. (4) By partitioning the interaction effect using orthogonal polynomials insight is gained into the nature of differences in relative growth rate. (5) By concentrating attention on the lower order terms of the polynomials, the influence of extraneous variation on conclusions may be minimized.