Question

II.10. More data on snakes. For a biology project, you measure the length (inches) and weight (ounces) of 12 snakes of the same variety.

  1. (a) Explain why you expect the correlation between length and weight to be positive.

  2. (b) The mean length turns out to be 20.8 inches. What is the mean length in centimeters? (There are 2.54 centimeters in an inch.)

  3. (c) The correlation between length and weight turns out to be r = 0.6. If you were to measure length in centimeters instead of inches, what would be the new value of r?

Figure II.3 plots the average brain weight in grams versus average body weight in kilograms for many species of mammals. There are many small mammals whose points at the lower left overlap. Exercises II.11 through II.16 are based on this scatterplot.

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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.