The meaning of a statistical process

A statistical ('stat') process is a continuous series of events that occur around an average of some kind but tend to be randomly more or less than that average by varying amounts.  If you look across the tops of a field of wheat, you will see that the plants are not all exactly the same height but that they are rather close to each other's height.  Of course, "rather close" is an subjective term.  If you were trying to get all the plants to be the same height, the variation you found might be quite annoying and depressing.  If you look at the field from a bit of a distance, the plant heights might appear to be exactly the same, making the field look like a velvet carpet, a smooth piece of felt.

The most famous statistical process MODEL produces a normal or "bell-shaped" distribution, which when graphed looks like a gentle mountain, with its peak in the center and slopes tailing off on either side from that peak.  Many people don't realize that the model is just that, a model.  A very precise mathematical formula exists, in several related forms, that creates the line seen in the various images at the link above.  An important cousin is the Poisson distribution but it does not have one characteristic, easily recognized shape.  The Poisson model does a better job at modeling relatively rare events, such as getting one or more flat tires.

If some process or set of occurrences is well-described by a statistical model, scientists may be able to estimate rather accurately how many examples of the events will occur.  Trying to estimate the number of hurricanes there will be in a given season might be done with a statistical model.

Even without statistics, finding a wheat plant that is 20 feet tall or 2 inches tall would tell us that the height of the plants might be changing.  Estimating the number of men of a given height or of girls who reach child-bearing readiness by age 10 could furnish a similar basis for concluding that men are getting taller or girls maturing earlier.  Humans are interested in reducing the uncertainty in life and statistical process modeling can help.