Title: Introduction to inference
Course: UGQuants (SSPS) > Section: Inference

This is the introduction to statistical inference.

This module looks at some of the basic applications of inferential statistics.

What are inferential statistics?

So far, we have taken our data and conducted some descriptive analysis of it: we have looked at frequency tables, measures of spread and central tendency, and we have looked at tables displaying two categorical variables. If we are only interested in a small group, say the students within our class, we do not need to infer - we can simply collect data on every student and work with that.

However, often we are interested in making statements about large populations - about all customers of a big online shop, about all pubs in the UK or about all people living in a country. In such cases, interviewing each customer, pub owner or person living in that country may prove way too expensive - and even impossible: not everyone may be willing to answer your questions.

This is where inferential statistics come into play: they allow us to only collect data on a subgroup (a sample) of everyone we actually want to say something about and infer from their responses what the answer for the whole population of interest is.

To keep it simple, we will not (yet) go into details about all the theory behind inferential statistics, but we need to cover two points before we can look at associations between two interval/ratio variables:

- hypothesis testing
- and significance.