Chapter 3.4, Problem 52PB

Gestational period and life expectancy Does the life expectancy of animals depend on the length of their gestational period? The data in the Animals file on the book’s website show observations on the average longevity (in years) and average gestational period (in days) for 21 animals. (Source: Wildlife Conservation Society)

1. a. Use the scatterplot below to describe the association. Are there any unusual observations?
2. b. Using software, verify the given numbers for the correlation and slope of the regression line shown on the plot.
3. c. Are there any outliers? If so, what makes the observations unusual? Would you expect any of them to be influential observations? Why or why not?
4. d. Find the regression line and the correlation without one of the observations identified in part c. Compare your results to those in part b. Was the observation influential? Explain.