Local environmentalists want to test if there is a difference in the pH of three different streams (called A, B, and C) feeding into Lake Travis. They took a random sample of 15 measurements from each stream and, after confirming all relevant assumptions, ran a one-way ANOVA on the data and got a significant (p<0.05) result.

a. Write the appropriate null and alternative hypotheses for this analysis. (1pt)
b. List one potential confounding variable and briefly describe what impact it might have on the applicability of the results. (2pt)