## Week 12, Inferential Statistics:

t-tests & correlations.

## Lecture notes

- Plato's Cave and the approximation of reality by science.
- Deductive v. Inductive reasoning and link between theory / hypothetical constructs & data.
- Sampling distribution, M of the sampling distribution
*Z, t,*critical ratio, statistical significance.- The Central Limit Theorem and sampling distributions.
- Correlations and assessing shared variance.
- Alpha (α), critical value.
- Type I error, Type II error.

This week we will discuss the t-test and correlation coefficient. Along the way we will learn a set of basic statistical concepts, some of which are cited in italics here.

Lecture notes: Statistics notes # 2

## Readings

Chapter 5 (further statistics) and readings on interpreting “relative risk” statistics, and interpreting data about risks + benefits of mammography .

## Discussion Group

Calculate your t-test, finish your Research Paper results section.

Compute a t-ratio by hand, and answer some questions about it. The sheet you need to hand in is here.

You used a worksheet for last week that you can use as a guide.

A PowerPoint show giving you instructions for deriving t is here.

A show describing the Central Limit theorum and using the t table is here.

A very cool demonstration of the Central Limit Theorem is here. Play it to see how larger & larger samples become more "normal".

By now, you have written your introduction and overall research design. Now take the data set we made up (or use your own) and analyze it to test your hypothesis. The data represents 10 participants in each of the experimental and control groups.

Your paper is due **next week**; so begin finishing up. Look at the paper assignment for guidance.