Then inferential analysis is a goal where you're actually

trying to take a small amount of data, on

a small number of observations, and sort of extrapolate

that information, or generalize that information to a larger population.

Inference is definitely the most common goal of most

statistical models, and most statistics you may have heard about.

It involves both estimating

some quantity that you're interested in and

also, more importantly maybe, the uncertainty

of that quantity that you're interested in.

And it depends heavily both on the

population that you're looking at, the group of

people or the group of objects that

you care about, and a sampling you've discovered.

So this is an example of, inferential analysis.

So the idea is, here, you're trying to look at the,

effect of air pollution control on life expectancy in the United States.

So, what they've done is, they haven't analysed all of the counties in the United

States, but they've analysed, so, sort of a

subset of the counties in the United States.

And they're using that to try to infer something about what's

generally happening in the relationship between air pollution and life expectancy.