# Psychology 242 Research in Psychology Dr. David J. McKirnan

## Lecture notes

Key topics:

• 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

Text:
Suggested background reading: "Introduction to Methods in Science" (or the eqivalent) in whatever text you are using.

Focus Modules:
The logic of Research: The allegory of Plato's Cave
Computing t
The Central Limit theorum

For lecture & Discussion Group:
• Read the articles / media cited below for discussion group.
• Listen to the NYC RadioLab PodCast about operationally defining death.
• 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.

You will use a t-test worksheet for this assignment.

A PowerPoint show giving you step by step 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.