A number of studies have shown lichens (certain plants composed of an alga and a fungus) to be excellent bioindicators of air pollution. The article “The Epiphytic Lichen Hypogymnia Physodes as a Biomonitor of Atmospheric Nitrogen and Sulphur Deposition in Norway” (Envir.

Monitoring and Assessment, 1993: 27–47) gives the following data (read from a graph) on wet deposition (g N/m2

) and (% dry weight): y 5 lichen x 5 NO3 Use the accompanying Minitab output to answer the following questions:

a. What are the least squares estimates of b0 and b1?

b. Predict lichen N for an deposition value of .5.

c. What is the estimate of s?

d. What is the value of total variation, and how much of it can be explained by the model relationship?
The regression equation is lichen no3 depo Predictor Coef Stdev t–ratio P Constant 0.36510 0.09904 3.69 0.004 no3 depo 0.9668 0.1829 5.29 0.000 Analysis of Variance SOURCE DF SS MS F P Regression 1 1.0427 1.0427 27.94 0.000 Error 11 0.4106 0.0373 Total 12 1.4533