Exercise R2.7 examined the correlation between BCI and pH in streams sampled in the Adirondack Mountains. Here is the corresponding regression model:

a) Write the regression model.
b) What is the interpretation of the coefficient of pH?
c) What would you predict the BCI would be for a stream with a pH of 8.2?

Data From Exercise R2.7

Biologists studying the effects of acid rain on wildlife collected data from 163 streams in the Adirondack Mountains. They recorded the pH (acidity) of the water and the BCI, a measure of biological diversity, and they calculated R² = 27%. Here’s a scatterplot of BCI against pH:

Transcribed Image Text:

Response variable is: BCI R squared = 27.1% s = 140.4 Variable Intercept pH Coefficient 2733.37 -197.694