# Chapter 12

# Introduction to Nonlinear Regression

**12.1** As θ_{2} decreases, the curve becomes steeper.

**12.3** As θ_{3} increases, the curve becomes steeper.

**12.5** **a.** As θ_{2} decreases, the curve becomes steeper.

**b.** As *x* → ∞, *E*(*y*) → 1.

**c.** When *x* = 0, *E*(*y*) = θ_{1} exp{−θ_{2}}.

**12.7** **a.** This is an intrinsically linear model.

**b.** The model is nonlinear.

**c.** The model is nonlinear.

**d.** This is an intrinsically linear model.

**e.** The model is nonlinear.

**12.9** = −.121

*x*_{2} + 1.066

*e*^{.4928x1}. An approximate 95% confidence interval for θ

_{3} is (−1.027, .785). Since this interval contains 0, we conclude there is no difference in the two days.

**12.11** **a.**

**b.** = .3896 − (−.2194)

*e*^{−.0992x}. The starting values were obtained by plotting ...