**Know for Quiz #1 on G & W Chs 1-4:**

This will test you on the basics of descriptive statistics: (1) presenting distributions of single variables graphically (tables, histograms), (2) describing distributions with words (such as skew, bimodal, rectangular); (3) summarizing distributions numerically (using parameters such as mean, median, variance, standard deviation).

**Note: **You may bring your calculator, but you may NOT consult notes or book during the quiz.

1. How a frequency table and histogram are constructed and how to interpret them. Be sure you know what is represented on each axis (x = horizontal axis, y = vertical axis) of a histogram.

2. Know the difference between discrete and continuous variables, and the four measurement scales (NOIR)

3. Be able to draw a normal distribution, a bimodal distribution, a skewed distribution (positive and negative), etc.

4. What mean, median, and mode are. Be able to calculate them given a set of scores. (NOTE: don't need to worry about interpolation for median). Know when you would use the median instead of the mean.

5. Know how skew affects the relative position of mean, median, and mode.

6. Know the four steps for calculating variance, and how to calculate the standard deviation, for both population and for samples (for samples, divide SS by n-1 instead of N).

7. The different symbols for variance (s-squared, sigma-squared, MS) and standard deviation (s, sigma), and other abbreviations such as SS. MS helps you remember the definition and formula for variance.