Some rice farmers burn their fields after harvest to remove leftover plant material and kill certain plant pests. you are researching the health effects of smoke from the rice burning. you interview some of the farmers, and they tell you that the smoke is harmless. how certain can you be about this information? 1. very certain, rice farmers know quite a bit about rice.
2. not very certain, the rice farmers might not tell you the truth about rice burning because it affects their business.
3. reasonably certain, rice is a food product, so it probably does not contain any toxic substances.