Techniques for gathering data: Sampling, experiment, simulation, census

What technique for gathering data (sampling, experiment, simulation or census) do you think was used in each of the following studies?
a) A computer program was used to model global weather patterns and to produce long-range weather forecasts for a rural agricultural region.
b) A random sample of 1,000 residents of a major metropolitan area was surveyed to determine the level of support for a new sports complex among all residents of the area.
c) To determine the effect of a new fertilizer on productivity of tomato plants one group of plants is treated with the new fertilizer while a second group is grown without such treatment. The number of ripe tomatoes produced by each group is counted.
d) A study was done regarding the number of home runs scored by major league baseball teams playing at altitudes over 5,000 feet. Data for all major league baseball games played at this altitude was used in the study.

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