User: | Open Learning Faculty Member:
I used the distance based method. The systematic sampling technique took the least amount of time, at 4 hrs, 5 mins, followed by haphazard at 4 hrs, 26 mins, and finally random which took 4 hrs, and 40 mins. Eastern hemlock and yellow birch were the two most common trees for each sampling technique. The sampling error was lowest for random (-1.7%, 29.8%) which would make it the most accurate, followed by haphazard (-6.5%, 31.7%) and systematic which had the highest error (-22.2%, 55%).
Striped maple and white pine were the two least common species for each sampling technique. Again, random (11.9%, -100%) was the most accurate, however systematic (60.6%, 123.8%) was more accurate than haphazard (118.3%, 124.7%) for the least common species. In general, the accuracy declined for rare species.
The percent error calculations are all quite large aside from the ones obtained in random sampling, and I believe this is due to the fact that 24 is too small a sample size. Generally as your sample size increases, your margins of error decrease (Statsoft, 2018) so I think increasing the sample size would yield more accurate results.
| Systematic | Sample time: 4 hrs, 5 mins | |||
| Actual Density | Data Density | % Error | ||
| Common | Eastern Hemlock | 469.9 | 365.8 | -22.2% |
| Yellow Birch | 108.9 | 168.8 | 55% | |
| Rare | Striped Maple | 17.5 | 28.1 | 60.6% |
| White Pine | 8.4 | 18.8 | 123.8% | |
| Random | Sample time: 4 hrs, 40 mins | |||
| Common | Eastern Hemlock | 469.9 | 461.8 | -1.7% |
| Yellow Birch | 108.9 | 141.4 | 29.8% | |
| Rare | White Pine | 8.4 | 9.4 | 11.9% |
| Striped Maple | 17.5 | 0 | -100% | |
| Haphazard | Sample time: 4 hrs, 26 mins | |||
| Common | Eastern Hemlock | 469.9 | 439.7 | -6.5% |
| Yellow Birch | 108.9 | 143.4 | 31.7% | |
| Rare | Striped Maple | 17.5 | 38.2 | 118.3% |
| White Pine | 8.4 | 19.1 | 127.4% | |
StatSoft. (2018). Designing and Experiment – Power Analysis. Retrieved February 2, 2018 from: http://www.statsoft.com/Textbook/Power-Analysis#power_doe3
