In an experiment to study factors influencing wood specific gravity (Anatomical Factors Influencing Wood Specific Gravity of
Question:
In an experiment to study factors influencing wood specific gravity (“Anatomical Factors Influencing Wood Specific Gravity of Slash Pines and the Implications for the Development of a High-Quality Pulpwood,” TAPPI, 1964: 401–404), a sample of 20 mature wood samples was obtained, and measurements were taken on the number of fibers/mm2 in springwood (x1), number of fibers/mm2 in summerwood (x2), % springwood (x3), light absorption in springwood (x4), and light absorption in summerwood (x5).
a. Fitting the regression function resulted in . Does the data indicate that there is a linear relationship between specific gravity and at least one of the predictors? Test using α = .01.
b. When x2 is dropped from the model, the value of R2 remains at .769. Compute adjusted R2 for both the full model and the model with x2 deleted.
c. When x1, x2, and x4 are all deleted, the resulting value of R2 is .654. The total sum of squares is SSE = .0196610 . Does the data suggest that all of x1, x2, and x4 have zero coefficients in the true regression model? Test the relevant hypotheses at level .05.
Chemistry The Central Science
ISBN: 978-0321696724
12th edition
Authors: Theodore Brown, Eugene LeMay, Bruce Bursten, Catherine Murphy, Patrick Woodward