Outliers. The African elephant is much larger than any other mammal in the data set but lies 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.

(a) If we removed the elephant, would this correlation increase or decrease or not change much? Explain your answer.

(b) If we removed dolphins, hippos, and humans, would this correlation increase or decrease or not change much? Explain your answer. (Hint: See page 318.)

Transcribed Image Text:

Brain weight (grams) 4000 4500 elephant 3500 3000- 2500 2000- 1500- 1000 500 0. 0 o dolphin o human 200- 400- F008 F009 hippo 1000 - 1200- 1400- 1600- 1800- 2000- 2200- 2400- 2600- 2800- Body weight (kilograms) Figure 11.3 Scatterplot of the average brain weight (grams) against the average body weight (kilograms) for 96 species of mammals, for Exercises II.11 to 11.16.