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NRM 340 – Final Exam Name ___________________ 1. Explain one advantage and one disadvantage for each of the following sampling schemes systematic sampling, simple random sampling, and stratified random sampling. 2. Match the following terms with the correct definition: a. carrying capacity b. evenness c. habitat ____ is the maximum number of animals of a given population that can be supported by available resources. ____ is the distribution of individuals among the species present ____ describes the resources and conditions present in an area that produce species occupancy (including survival and reproduction) 3. If the standard deviation of a sample of 72 tree diameters (dbh) is 8 cm calculate the standard error of the mean. 4. If the mean diameter in the previous problem was found to be 20 cm what would be the coefficient of variation? 5. What phrase best describes the meaning of “the standard error of the mean”? a. b. c. d. the mean deviation of the measurements the mean of the means the standard deviation of the means the coefficient of determination 6. Compare the variability in tree heights in a 20-year-old natural stand of balsam fir with those in a 4-year-old plantation, given the following data: Natural Stand mean = 40 ft standard deviation = 4.4 ft Plantation = 5.9 ft standard deviation = 0.649 ft mean 7. What are the three main components of habitat? 8. The following volume data were computed from 15 1/5-acre line-cruise plots on a 34-acre tract: Plot 1 2 3 4 5 Volume (ft3/plot) 500 710 425 900 610 Plot 6 7 8 9 10 Volume (ft3/plot) 415 310 200 490 600 Plot 11 12 13 14 15 The average volume per plot was calculated as 516 ft3. Calculate: a. The estimated volume per acre b. The estimated volume for the entire tract 9. Explain what a 95% confidence interval means. Volume (ft3/plot) 470 545 450 605 510 10. Calculate Simpson’s Index for the following data: Species 1 2 3 Abundance 50 25 10 11. How do you interpret the Simpson’s Index value calculated above? 12. You are given the following information: Stratum 1 2 3 Acreage 125 190 50 # of 1/10-acre Plots 35 52 13 Average Volume (ft3/plot) 275 312 178 Calculate: a. an estimate of the overall population mean b. the standard error of the population (w/o replacement) c. a 95% confidence interval for the population d. determine the correct proportional allocation of the samples Variance 24,000 32,000 18,000 13. True or False? Richness is the number of units (i.e., species, ecosystems, etc.) per unit area. 14. Eleven 1/20-acre sample plots were measured in a 50-acre tract for cubic foot volume of pulpwood-size trees. The data are as follows: Yi (ft3/plot) Plot 1 2 3 4 5 6 7 8 9 10 11 75 75 68 92 75 44 92 44 75 48 68 Calculate the following: a. The sample mean. b. The sample mode. c. The sample median. 15. You have collected data on weight of moose forage for a willow shrub site and have found for a sample size of 16 that the mean weight per plot (1/10-acre) is 24 kg with a coefficient of variation of 50%. Calculate the 95% confidence limits: 16. Suppose we have conducted a preliminary inventory of 25 plots to estimate volume per acre of a timber stand. From that sample we estimated the mean to be 4,400 board feet per acre and a standard deviation of 2,000 board feet per acre. Determine the sampling intensity needed to be within plus-or-minus 5% of the mean, with a confidence level of 95%. 17. You are told to develop a stratified random sample and allocate a total of 150 1/10-acre plots. You are given the following information: h 1 2 3 4 Nh 15 45 110 60 Sh 20 70 35 45 a. Allocate these optimally to reduce variability within strata. 18. A forester wishes to estimate the proportion of surviving seedlings in a young plantation. The seedlings were planted at regular spacing and the forester randomly surveyed 50 seedlings, finding 40 of the seedlings to be alive. The total number of seedlings planted in the plantation was 5,000. Calculate a 95% confidence interval. 19. What is the difference between a dendrometer and hypsometer?