Example 4.3. A Central Condence Interval for a Poisson Parameter Foresters are concerned about the number of young trees destroyed by deer. Suppose a forester chooses 4 quarter-acre quadrants at random and nds that in the four plots 8 young trees have been destroyed by deer. She wants to estimate the damage rate per acre by an approximate 80% condence interval. Using Table A7, she nds that 8 is in the region of acceptance for A = 5.0 to A = 12.0, so the condence interval is (310302 5.0 S A S 12.0 in which A is the damage rate per acre. The upper and lower bounds on the condence interval are limited to column entries in Table AT! so, as was done with the binomial distribution, another table, Table A.8, is given for obtaining more precise upper and lower limits for the condence interval. Using the same data above, the forester would enter Table A.8 with row entry y = 8 and column entry 1 a = 0.80; she would nd L = 4.6561 and U = 12.9947, and she obtains the condence interval C1030: 4.7