After reading this chapter, you should be able to:

1. State two reasons why it is important to summarize data.
2. Define descriptive statistics and explain how they are used to describe data.
3. Identify and construct tables and graphs for frequency distributions.
4. Identify and describe the different types of frequency distributions.
5. Identify and appropriately use the mean, median, and mode to describe data.
6. Identify and appropriately use the variance and standard deviation to describe data.
7. Define and apply the empirical rule.
8. Identify and construct graphs used to display group means and correlations.
9. Use Cronbach’s alpha and Cohen’s kappa to estimate reliability.
10. Distinguish between standard scores, z scores, percentile ranks, and age/grade equivalents.