## Week 11,
Basic Statistics:

Scales, distributions, variance, the normal distribution
.

## Lecture notes

Key topics:

- Using numbers to represent “reality”:
- Key role in science
- Problems and potential political biases.

- Types of numbers:
- Scales:
*ratio, interval, ordinal, categorical* - Frequencies, frequency distributions

- Scales:
- Characterizing trends in data:
- measures of
*central tendency*; mean (*M*), mode, median. - measures
of
*variance*: range and**standard deviation**

- measures of
- The
*Normal distribution*& statistical decisions - The
*critical ratio*and hypothesis testing.

Understand all the italicized terms: they will be crucial to the entire statistics section.

The properties of the normal distribution in particular are central to this section.

The lecture notes are here.

## Readings

Chapter 4 (or the basic statistics chapter) of your text.

Other readings: politics and statistics, political uses of science, fraud in education tracking.

## Discussion Group

**Get a jump on the t-test you will have due for next week (and to complete your paper):
Go to the discussion group assighment for next week and begin working on it now.
We will be using a t-test worksheet for that assignment. **

Basic frequency distributions.