13.68 The figure at the top of the page is based on data from the article “Root and Shoot Competition Intensity Along a Soil Depth Gradient” (Ecology [1995]:

673– 682). It shows the relationship between aboveground biomass and soil depth within the experimental plots. The relationship is described by the estimated regression equation: biomass 5 29.85 1 25.29(soil depth)

and r2 5 .65; P , 0.001; n 5 55. Do you think the simple linear regression model is appropriate here? Explain.

What would you expect to see in a plot of the standardized residuals versus x?

Transcribed Image Text:

Biomass (g/m) 600 400 200 0 0 5 10 Soil depth (cm) 15 20