Soon or later those conducting data mining studies will need to compute standard errors for several statistics.

Every statistic from a sample distribution has a standard error that is specific to that statistic. Using the incorrect definition for a standard error invalidates any research study.

An updated and improved tutorial on standard errors is given below, showing what is/is not a standard error. The difference between sampling distributions and the distribution of samples is at the core of its meaning, something that not many seem to grasp (seos, marketers, pseudo-scientists,…).

http://www.minerazzi.com/tutorials/a-tutorial-on-standard-errors.pdf