Question: Acid rain. 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:
a) What is the correlation between pH and BCI?
b) Describe the association between these two variables.
c) If a stream has average pH, what would you predict about the BCI?
d) In a stream where the pH is 3 standard deviations above average, what would you predict about the BCI?