## Questions and Assignments to Lecture 2

2.1. What is population density?

2.2. The weed is more abundant at the edges of the field. Weed biomass is sampled at random locations within the field. Can we use equation

to estimate the standard error of mean weed biomass per sq.m.? If not, then what options do we have?

2.3. What is correlogram?

2.4. Density of the Colorado potato beetle should be estimated with accuracy A = 0.1 (10%). Preliminary sampling (N = 30) indicated: M = 0.5 beetles/plant, SD = 0.9 beetles/plant. How many additional samples you need?

2.5. Solve the ordinary kriging system for two sample points:

z are variable values at sample points; estimate z-value at the estimation point.

2.6. Sampling of the European pine sawfly was performed separately within 1 m radius around trees and outside of these circles using 0.25 sq.m. squares:

 Stratum % area No. of samples Mean SD Near trees 30 40 32 18 Far from trees 70 20 12 7

Estimate average sawfly density and its standard error in the entire area

2.7. Estimate the size of the population of perch in a pond from capture-recapture data: 284 fish were netted, marked and released; 1392 fish were caught after 2 days, and 86 of them were found to be marked. (use Lincoln index)

Alexei Sharov 1/12/96