Direct drivers of deforestation in Amazon countries Cattle ranching Cattle ranching is the leading cause of deforestation in the Amazon rainforest. In Brazil, this has been the case since at least the 1970s: government figures attributed 38 percent of deforestation from 1966-1975 to large-scale cattle ranching.
The sampling frequency or sampling rate, fs, is the average number of samples obtained in one second (samples per second), thus fs = 1/T. Reconstructing a continuous function from samples is done by interpolation algorithms.
In our example, imagine that you chose 4. Now, to select the sample, start with the 4th unit in the list and take every k-th unit (every 5th, because k=5). You would be sampling units 4, 9, 14, 19, and so on to 100 and you would wind up with 20 units in your sample. In order for systematic sampling to work, it is essential that the units in the population be randomly ordered, at least with respect to the characteristics you are measuring.