The article “The Respiration in Air and in Water of the Limpets Patella caerulea and Patella lusitanica” (Comp.

Biochemistry and Physiology, 1975: 407–411) proposed a simple power model for the relationship between respiration rate y and temperature x for P. caerulea in air. However, a plot of ln(y) versus x exhibits a curved pattern. Fit the quadratic power model to the accompanying data.

x 10 15 20 25 30 y 37.1 70.1 109.7 177.2 222.6 Y 5 aebx1gx2 # P bˆ

2 bˆ

2x 2 bˆ

0 1 bˆ

1x 1 mY#

50 b*2 b*1 b*0 y 5 b*0 1 b*1 xr 1 b*2 (xr)2 xr 5 (x 2 x)/sx y 5 exchangeable x 5 acid x 5 10 15 20 25 30 35 y .985 .996 .988 .962 .940 .915 .878 Parameter Estimate Estimated SD

.9671 .0026

.0502 .0051

.0176 .0023

.0062 .0031

a. What value of y would you predict when the half-divergence angle is 20? When ?

b. What is the estimated regression function for the “unstandardized” model?

c. Use a level .05 test to decide whether the cubic term should be deleted from the model.