Random variables are used to model situations in which the outcome, before the fact, is uncertain. One component in the model is the sample space. The sample space is the list of all possible outcomes (or a range of possible values). For each value in the sample space, there is an associated probability.The probability can either be an estimate of something that exists in the real world or it could be an exact value that comes from an ideal distribution.Sometimes identifying the sample space helps to remind you exactly what it is that you are measuring.

I need to think of something that I might want to measure that is affected by random variation. I also need to identify what I want to measure and then describe its approximate sample space. After this, I need to give a rough description of the prababilities associated with those values. (I can simply specify if they are all the same probability or if values in one range will be more likely than values in another range). I think to think of what I could say to a person who says that he knows what the outcome of an individual observation will be, which has not happened yet and may have an error. When forming your answer to this question I need to give an example of a situation from a field of interest for which a random variable can serve as a model.