Int. J. Environ. Res. Public Health 2011, 8 578 21. Salant, P.; Dillman, D.A. How to Conduct Your Own Survey; John Wiley & Sons: New York, NY, USA, 1994; pp. 137-147. 22. Hawaii was removed from the study due to its uniqueness in geography and climate, which does not much resemble the rest three states of its region. 23. Hosmer, D.W.; Lemeshow, S. Applied Logistic Regression, 2nd ed.; John Wiley & Sons: New York, NY, USA, 2000. 24. Source information from Texas Groundwater Protection Committee. Available online: http://www.tgpc.state.tx.us/DrinkingWater.htm (accessed on 28 September 2010). 25. Gustafson, P.E. Gender differences in risk perception: theoretical and methodological perspectives. Risk Anal. 1998, 18, 805-811. 26. Dosman, D.M.; Adamowicz, W.L.; Hrudey, S.E. Socioeconomic determinants of health- and food safety-related risk perceptions. Risk Anal. 2001, 21, 307-317. Appendix 1 A separate analysis, a one-way ANOVA (analysis of variance) was done to compare regional differences in bottled water use for primary drinking purposes. Table 1 shows bottled water use in each region and differences with statistical significance. The variable (primarily purchase bottled water for drinking) is a dichotomous variable with two possible responses 0 (not purchase) and 1 (purchase bottled water for drinking). Therefore the following means reflect proportion of respondents responding with 1 in each region. Post-hoc Bonferroni pair tests were conducted on the means and the last column of the following table shows regions with significant differences (at 0.05 level). For example, the first row shows that region 4 has mean which is significantly different from that of region 6, 7, 8, and 9, respectively. Table 1. Bottled water use by region. Region R4 R6 R7 R8 R9 N 1,344 1,122 932 993 1,432 Mean 0.136 0.185 0.045 0.063 0.198 S.D. 0.343 0.389 0.208 0.244 0.398 Regions with significant differences R6, R7, R8, R9 R4, R7, R8 R4, R6, R9 R4, R6, R9 R4, R7, R8 Region 9 and region 6 have significantly higher percent of primary bottled water users, followed by region 4. Region 7 and region 8 have the least primary bottled water users. © 2011 by the authors; licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution license (http://creativecommons.org/licenses/by/3.0/).