The article “The Lubrication of Metal-on-Metal Total Hip Joints: A Slide Down the Stribeck Curve” (S. Smith, D. Dowson, and A. Goldsmith, Proceedings of the Institution of Mechanical Engineers, 2001:483–493) presents results from wear tests done on metal artificial hip joints. Joints with several different diameters were tested. The data presented in the following table on head roughness are consistent with the means and standard deviations reported in the article.
Head Roughness (nm)
0.83 2.25 0.20 2.78 3.93
2.72 2.48 3.80
5.99 5.32 4.59
a. Construct an ANOVA table. You may give a range for the P-value.
b. Can you conclude that mean roughness varies with diameter? Explain.