Eye anatomy of giraffes. Giraffes are believed to have excellent vision. The journal African Zoology (Oct.

2013) published a study of giraffe eye characteristics.

Data were collected for a sample of 27 giraffes inhabiting southeastern Zimbabwe. Of interest to the researchers was how these eye characteristics relate to a giraffe’s body mass. They fit a simple linear regression equation of the form ln1y2 = b0 + b1 ln1x2 +

e, where y represents an eye characteristic and x represents body mass (measured in kilograms). For this model, the slope b1 represents the percentage change in y for every 1% increase in x.

a. For the eye characteristic y = eye mass (grams), the regression equation yielded the following 95%

confidence interval for b1: 1.25, .302. Give a practical interpretation of this interval.

b. For the eye characteristic y = orbit axis angle (degrees), the regression equation yielded the following 95% confidence interval for b1: 1 -.14, -.052. Give a practical interpretation of this interval.