An article in Cancer Epidemiology, Biomarkers and

Chapter 12, Problem 16E

(choose chapter or problem)

An article in  Cancer Epidemiology, Biomarkers and Prevention  (1996,  Vol. 5, pp. 849–852) reported on a pilot study to assess the use of toenail arsenic concentrations as an indicator of ingestion of arsenic-containing water.  Twenty-one participants were interviewed regarding use of their private (unregulated) wells for drinking and cooking, and each provided a sample of water and toenail clippings. Table E12-8 showed the data of age (years), sex of person (1 = male, 2 = female), proportion of times household well used for drinking 114214312434534 \(\leq===\geq\)  \((/, /, /, /, /)\) proportion of times household well used for cooking \(\leq\) , (1 1/4, 2 = 1/4, 3 = 1/2, 4 = 3/4, 5 3/4) \(\geq\), arsenic in water (ppm), and arsenic in toenails (ppm) respectively

Fit a multiple linear regression model using arsenic concentration in nails as the response and age, drink use, cook use, and arsenic in the water as the regressors. Estimate \(\sigma^{2}\) and the standard errors of the regression coefficients. Use the model to predict the arsenic in nails when the age is 30, the drink use is category 5, the cook use is category 5, and arsenic in the water is 0.135 ppm.

Equation Transcription:

   

   

     

Text Transcription:

\leq===\geq

(/, /, /, /, /)

\leq

\geq

\sigma^2