Focus Problem: Wood Duck Nests In the Focus Problem at the beginning of this chapter, a study was described comparing the hatch ratios of wood duck nesting boxes. Group I nesting boxes were well separated from each other and well hidden by available brush. There were a total of 474 eggs in group I boxes, of which a field count showed about 270 had hatched. Group II nesting boxes were placed in highly visible locations and grouped closely together. There were a total of 805 eggs in group II boxes, of which a field count showed about 270 had hatched.

(a) Find a point estimate pˆ1 for p1, the proportion of eggs that hatched in group I nest box placements.

Find a 95% confidence interval for p1.

(b) Find a point estimate pˆ2 for p2, the proportion of eggs that hatched in group II nest box placements.

Find a 95% confidence interval for p2.

(c) Find a 95% confidence interval for p1 2p2. Does the interval indicate that the proportion of eggs hatched from group I nest boxes is higher than, lower than, or equal to the proportion of eggs hatched from group II nest boxes?

(d) Interpretation What conclusions about placement of nest boxes can be drawn? In the article discussed in the Focus Problem, additional concerns are raised about the higher cost of placing and maintaining group I nest box placements. Also at issue is the cost efficiency per successful wood duck hatch.

AppendixLO1