Statistical analysis enables researchers to organize, interpret, and communicate numeric information. Mathematic skill is not required to grasp statistics—only logical thinking ability is needed. In this book, we underplay computation. We focus on explaining which statistics to use in different situations and on how to understand what statistical results mean.
Statistics can be descriptive or inferential. Descriptive statistics are used to describe and synthesize data (e.g., a percentage). When a percentage or other descriptive statistic is calculated from population data, it is called a parameter . A descriptive index from a sample is a statistic . Research questions are about parameters, but researchers calculate statistics to estimate them and use inferential statistics to make inferences about the population. This chapter discusses descriptive statistics, and Chapter 17 focuses on inferential statistics. First we discuss levels of measurement because the….