Question

II.13. Outliers. African elephants are much larger than any other mammal in the data set but lie roughly in the overall straight-line pattern. Dolphins, humans, and hippos lie outside the overall pattern. The correlation between body weight and brain weight for the entire data set is r = 0.86.

  1. (a) If we removed elephants, would this correlation increase, decrease, or not change much? Explain your answer. (Hint: See page 326.)

  2. (b) If we removed dolphins, hippos, and humans, would this correlation increase, decrease, or not change much? Explain your answer. (Hint: See page 326.)

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Figure II.3: Figure II.3 Scatterplot of the average brain weight (grams) against the average body weight (kilograms) for 96 species of mammals, Exercises II.11 through II.16.