The technique with the fastest sampling time was Random at 4 hours, 43 minutes, followed by 12 hours, 6 minutes for systematic along a topographical gradient, and finally 13 hours, 4 minutes for haphazard or subjective sampling.
Table 1
| Estimated | Estimated | Estimated | |||||
| Species | Actual Density | Systematic Sampling Density | %Error: Systematic Sampling | Random Sampling Density | %Error: Random Sampling | Haphazard Sampling Density | %Error Haphazard Sampling |
| Eastern Hemlock | 469.9 | 429.2 | -9% | 347.2 | -26% | 556 | 18% |
| Red Maple | 118.9 | 79.2 | -33% | 93.1 | -22% | 132 | 11% |
| Sweet Birch | 117.5 | 62.5 | -47% | 135.5 | 15% | 168 | 43% |
| Yellow Birch | 108.9 | 141.7 | 30% | 76.2 | -30% | 112 | 3% |
| Chestnut Oak | 87.5 | 79.2 | -9% | 127 | 45% | 144 | 65% |
| Striped Maple | 17.5 | 16.7 | -5% | 25.4 | 45% | 0 | -100% |
| White Pine | 8.4 | 0 | -100% | 8.5 | 1% | 8 | -5% |
| %Average Error for Method | 33% | 26% | 35% |
Table 1 above uses (E – T)/T*100, where E = estimated value and T = true value to calculate percentage error.
The two most common species were the Eastern Hemlock and the Red Maple, showing densities of 469.9 and 188.9, respectively. Their calculated percentage errors were 9%, 26%, and 18% (SSD, RSD, HSD) for the Eastern Hemlock and 33% (SSD), 22% (RSD), and 11% (HSD) for the Red Maple.
The two rarest species were the White Pine (8.4) and the Chestnut Oak (87.5), with calculated percentage error being 100% (SSD), 1% (RSD), and 5% (HSD) for White Pine and 9% (SSD), 45% (RSD), and 65% (HSD) for Chestnut Oak.
I sorted species by actual density and made an average % error row to sum average % error per sampling method. This showed a trend in accuracy with species abundance where increased abundance had generally lower margins of error. It further revealed RSD to have the lowest % error and HSD to have the highest. The differences were marginal, however, and a simple sum of average errors is skewed, since an expected result of 0 and a finding of 8.4 density will yield a number like 100%, which significanltly increases average error.
Oh, I fixed my %sum error.
Just summing colums and then making a %error from the totals gave more accurate results with RSD at 12%, SSD at 13%, and HSD at 21%
See Table 2 Below
Estimated Estimated Estimated
Species Actual Density Systematic Sampling Density %Error: Systematic Sampling Random Sampling Density %Error: Random Sampling Haphazard Sampling Density %Error Haphazard Sampling
Eastern Hemlock 469.9 429.2 -9% 347.2 -26% 556 18%
Red Maple 118.9 79.2 -33% 93.1 -22% 132 11%
Sweet Birch 117.5 62.5 -47% 135.5 15% 168 43%
Yellow Birch 108.9 141.7 30% 76.2 -30% 112 3%
Chestnut Oak 87.5 79.2 -9% 127 45% 144 65%
Striped Maple 17.5 16.7 -5% 25.4 45% 0 -100%
White Pine 8.4 0 -100% 8.5 1% 8 -5%
%Average Error for Method 928.6 808.5 -13% 812.9 -12% 1120 21%
Sorry, formatting doesn’t seem to work the same in comments. Just see last row =)