Biologists studying the effects of acid rain on wildlife collected data from 172 streams in the Adirondack Mountains. They recorded the pH (acidity) of the water and the BCI, a measure of biological diversity. Here's a scatter plot of BCI against pH for the 163 streams for which we have these data:

And here is part of the regression analysis:
Dependent variable is BCI
R-squared = 27.1%
s = 140.4 With 163 €“ 2 = 161 degrees of freedom

a) State the null and alternative hypotheses under investigation.
b) Assuming that the assumptions for regression inference are reasonable, find the t- and P-values.
c) State your conclusion.

Transcribed Image Text:

1500 身* 250!I.i 2 1000 750 6.8 7.2 7.6 8.0 pH Variable Coefficient SE(Coeff) Intercept 2733.37 187.9 pH -197.69425.57