0 ≤ r2 ≤ 1 since -1 ≤ r ≤ 1

  • r2 is the percent of variation in the response variable that can be explained by the least squares regression of the response variable on the explanatory variable.
  • For example: 84.4% of the variability in number of shark attacks can be explained by the LS regression of shark attacks on human population.