This chapter provides an introduction to descriptive statistics. Specifically, this chapter covers some basic material related to describing and displaying the order in a group of numbers. After reading this chapter, you should:
- understand what is meant by descriptive statistics;
- understand and be able to use the terms variable, value, and score;
- understand the difference between an equal-interval variable, a rank-order variable, and a nominal variable;
- understand how to make a frequency table and a grouped frequency table;
- understand how to make a histogram and a frequency polygon;
- be able to describe the shape of a frequency distribution using the terms unimodal, bimodal, multimodal, and rectangular;
- be able to describe the shape of a frequency distribution using the terms symmetrical and skewed;
- understand the difference between a floor effect and a ceiling effect;
- be able to describe the shape of a frequency distribution using the terms heavy-tailed and light-tailed;
- understand what is meant by the normal curve.
