The invasive diatom species Didymosphenia geminata has the potential to inflict substantial ecological and economic damage in rivers. The article “Substrate Characteristics Affect Colonization by the...

The invasive diatom species Didymosphenia geminata has the potential to inflict substantial ecological and economic damage in rivers. The article “Substrate Characteristics Affect Colonization by the Bloom-Forming Didymosphenia geminata” (Aquatic Ecology, 2010: 33–40) described an investigation of colonization behavior. One aspect of particular interest was whether y = colony density was related to x = rock surface area. The article contained a scatterplot and summary of a regression analysis. Here is representative data:

a. Determine the equation of the least squares line for this data and then calculate and interpret the coefficient of determination.

b. The second observation has a very extreme y value (in the full data set consisting of 72 observations, there were 2 of these). This observation may have had a substantial impact on the form of the regression function and subsequent conclusions. Eliminate it and redo part (a). What do you conclude?