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 = β0 + β1 In (x) + (, where y represents an eye characteristic and x represents body mass (measured in kilograms). For this model, the slope β1 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 β1: (.25, .30). 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 β1: (-.14, -.05). Give a practical interpretation of this interval.