this might be a bit of an uneducated question, but I want to make sure I don't get anything wrong.

I'm wondering if one can draw conclusions regarding probability/frequency distribution/density of a population from a sample. I often see descriptive patterns in research papers concluding that a variable X distributes in some way regarding the manifestation of a variable y (e.g. companies raise either the money needed [100%] or barley anything from investors[0-5%]). They show this in some ordinary two dimensional coordinate system and assume this holds true in general (and thus the whole population).

- Now, since descriptive statements only hold true for a sample, shouldn't the above be an invalid conclusion?
- And if so, how does one derive the true probability/frequency distribution/density of a population from a sample?