Purpose: Present an analysis method for survey results from beach litter inventories on Lake Geneva.
Background: This is in the context of the global movement to reduce plastic debris in the maritime environment. Riverine inputs are major contributors of plastic debris (and all types of refuse) to the oceans. This is an analysis of the data collected on the shores of Lake Geneva over a three year period. The maritime protocol was modified in very specific ways to adjust for the local geography and population density.
If sampling all the trash is not possibile, what if we sample as much as possible and see what that looks like? The following questions could be answered:
In notebook one the conclusion was that the data has different geographic centers and those centers reflect different land use patterns.
The data is now local so it is allways best to run notebook one first
This notebook and all subsequent use the directory establsihed in notebook one (see above)
Reported as the total number of objects found, the cumulative and year over year results are given in the table below:
Statistic | Year one | Year two | Year three | All |
---|---|---|---|---|
Samples | 83 | 41 | 24 | 148 |
mean | 8.77 | 9.99 | 9.01 | 9.16 |
median | 4.83 | 6.84 | 4.24 | 5.52 |
Std dev | 9.92 | 8.52 | 16.14 | 10.75 |
25\%ile | 3.113 | 4.41 | 2.36 | 3.18 |
75\%ile | 10.405 | 12.35 | 7.79 | 11.24 |
Minimum | 0.68 | 0.57 | 0.11 | 0.11 |
Maximum | 50.075 | 39.54 | 77.05 | 77.05 |
MCBP samples | 80 | 22 | 5 | 107 |
SLR samples | 0 | 18 | 15 | 33 |
EPFL samples | 2 | 2 | 2 | 6 |
PC samples | 0 | 0 | 2 | 2 |
Year two has the highest average, median and the greatest innerquartile range. The lowest and the highest daily values were reported in year three. In each year there is one group that collected at least 50% of all the samples.
For each year the mean is greater than the median, suggesting a right skewed distribution. The mean and median are clossest at year two.