According to what I read online, the error term and the residual are often interchangeable. Please let me know if my understanding below is correct:
However, the difference is that the error term is the difference between our predicted value and the ACTUAL population value. So for instance, if we are to measure the relationship between salary level and experience level for a 35 year old male in the US, we wouldn't be able to get the data for ALL of the millions of 35 year old males in the US. However, we can get a sample population of that whole population. So therefore, our regression of Y would include an error term which indicates the value of what we have and the ACTUAL value of the population that we CANNOT OBSERVE. However, the RESIDUAL is the difference between the actual regression line and the actual POINTS of the scatter plot of data that we have that we have actually OBSERVED from going out and collecting data from some source we may have.
Is my understanding correct?