In a capture- recapture survey, 10,000 salmon were released after marking by inserting small wires. When 6000 fish from the population were subsequently caught, 400 of the wire tags were discovered by running the fish through a metal detection device.
(a) Estimate the number of fish in the population
(b) Give an approximate 95% confidence interval for the estimate.
(c) Suppose that the detection device missed some of the wire tags. Would overestimation or underestimation of the population tend to result?
(d) If the wire tags caused significant numbers of fish to die soon after release, would overestimation or underestimation tend to result?