User: | Open Learning Faculty Member:
The technique that is most time-efficient for area sampling is haphazard, with a total time of 12 hours and 29 minutes. Systemic sampling took 12 hours and 36 minutes, and random sampling took 12 hours and 45 minutes.
Eastern Hemlock – Most Common
- Actual Density: 469.9
- Systemic Sampling: 524.0; Percentage Error: 11.5%
- Random: 666.7; Percentage Error: 41.9%
- Haphazard: 650.0; Percentage Error: 38.3%
Red Maple
- Actual Density: 118.9
- Systemic Sampling: 100.0; Percentage Error: 15.9%
- Random: 79.2; Percentage Error: 33.4%
- Haphazard: 112.5; Percentage Error: 5.4%
White Pine – Most Rare
- Actual Density: 8.4
- Systemic Sampling: 12.0; Percentage Error: 42.9%
- Random: 8.3; Percentage Error: 1.2%
- Haphazard: 0.0; Percentage Error: 100%
Striped Maple
- Actual Density: 17.5
- Systemic Sampling: 12.0; Percentage Error: 31.3%
- Random: 66.7; Percentage Error: 281.1%
- Haphazard: 20.8; Percentage Error: 18.9%
Sweet Birch
- Actual Density: 117.5
- Systemic Sampling: 136.0; Percentage Error: 15.7%
- Random: 170.8; Percentage Error: 45.4%
- Haphazard: 183.3; Percentage Error: 56.0%
Yellow Birch
- Actual Density: 108.9
- Systemic Sampling: 128.0; Percentage Error: 17.5%
- Random: 70.8; Percentage Error: 35.0%
- Haphazard: 162.5; Percentage Error: 49.2%
Chestnut Oak
- Actual Density: 87.5
- Systemic Sampling: 104.0; Percentage Error: 18.9%
- Random: 54.2; Percentage Error: 38.0%
- Haphazard: 54.2; Percentage Error: 38.0%
When comparing the two most common species, the most accurate sampling strategy for Eastern Hemlock was systemic sampling with a percentage error of 11.5%. The most accurate sampling strategy for Red Maple was haphazard sampling, with a percentage error of 5.4%. If you average the percentage errors of the two species of systemic vs. haphazard sampling, the average error of systemic is 13.7% and haphazard is 21.9%. Therefore, the most accurate sampling strategy is systemic sampling.
When comparing the two most rare species, the most accurate sampling strategy for White Pine was random sampling with a percentage error of 1.2%. The most accurate strategy for the Striped Maple was haphazard sampling with a percentage error of 18.9%. Comparing the averages of the percentage errors for these two strategies, the most accurate sampling strategy is haphazard with an average percentage error of 59.5%. The average percentage error of random sampling is 141.2%. The accuracy of the sampling appears to decline with rarer species, as evidenced by the increase in the percentage error averages.
I do not believe that 24 was a sufficient number of sample points. As the density of the tree species varies so greatly throughout the study area, using this number of points resulted in missing some species in the sample that were present. For example, although the density of White Pine trees was 8.4, with haphazard sampling this species was not sampled resulting in a 100% percentage error.
