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15 Examples 291200 600 1000 14005 MarginalTrunk circumference (mm)20015010050oooooo31ooooooooooo42oooo2001501005020015010050ooooo o oooooooo200 600 1000 1400Time since December 31, 1968 (Days)Figure 15.15: Trellis plot of trunk circumference for each tree at sample dates (adjustedfor season effects), with fitted profiles across time and confidence intervalsFigure 15.15 presents the predicted growth over time for individual trees and amarginal prediction for trees with approximate confidence intervals (2±× standarderror of prediction). Within this figure, the data is adjusted to remove theestimated seasonal effect. The conclusions from this analysis are quite differentfrom those obtained by the nonlinear mixed effects analysis. The individualcurves for each tree are not convincingly modelled by a logistic function. Figure15.16 presents a plot of the residuals from the nonlinear model fitted on p340of Pinheiro and Bates (2000). The distinct pattern in the residuals, which is thesame for all trees is taken up in our analysis by the season term.