According to Pandey et al. (A-3) carcinoma of the gallbladder is not infrequent. One of the primary risk factors for gallbladder cancer is cholelithiasis, the asymptomatic presence of stones in the gallbladder. The researchers performed a case-control study of 50 subjects with gallbladder cancer and 50 subjects with cholelithiasis. Of interest was the concentration of lipid peroxidation products in gallbladder bile, a condition that may give rise to gallbladder cancer. The lipid peroxidation product melonaldehyde (MDA, mg=mg) was used to measure lipid peroxidation. One of the independent variables considered was the cytochrome P-450 concentration (CYTO, nmol/mg). Researchers used disease status (gallbladder cancer vs. cholelithiasis) and cytochrome P-450 concentration to predict MDA. The following data were collected.

Cholelithiasis Gallbladder Cancer MDA CYTO MDA CYTO MDA CYTO MDA CYTO 0.68 12.60 11.62 4.83 1.60 22.74 9.20 8.99 0.16 4.72 2.71 3.25 4.00 4.63 0.69 5.86 0.34 3.08 3.39 7.03 4.50 9.83 10.20 28.32 3.86 5.23 6.10 9.64 0.77 8.03 3.80 4.76 0.98 4.29 1.95 9.02 2.79 9.11 1.90 8.09 3.31 21.46 3.80 7.76 8.78 7.50 2.00 21.05 1.11 10.07 1.72 3.68 2.69 18.05 7.80 20.22 4.46 5.03 9.31 11.56 0.80 3.92 16.10 9.06 1.16 11.60 3.25 10.33 3.43 22.20 0.98 35.07