Chapter 4.4, Problem 22E

Special Rounding Instructions For this exercise set, round all regression parameters to three decimal places, but round all other answers to two decimal places unless otherwise indicated.

Gray Wolves in Wisconsin Gray wolves were among the first mammals protected under the Endangered Species Act in the $1970\text{s}$. Wolves recolonized in Wisconsin beginning in $1980$.Their population grew reliably after $1985$ as follows:

Year	Wolves	Year	Wolves
$1985$	$15$	$1993$	$40$
$1986$	$16$	$1994$	$57$
$1987$	$18$	$1995$	$83$
$1988$	$28$	$1996$	$99$
$1989$	$31$	$1997$	$145$
$1990$	$34$	$1998$	$178$
$1991$	$40$	$1999$	$197$
$1992$	$45$	$2000$	$266$

a. Explain why an exponential model may be appropriate.

b. Are these data exactly exponential? Explain.

c. Find an exponential model for these data.

d. Plot the data and the exponential model.

e. Comment on your graph in part d. Which data points are below or above the number predicted by the exponential model?