Understanding and Applying Research Design

DATA MANAGEMENT UNIT C: DESCRIPTIVE STATISTICS¹

Statistical procedures are best used to discover patterns in the data that are not directly observable. Bringing light to these patterns allows researchers to understand and engage in problem solving. This section describes descriptive statistics for each of the major levels of data: nominal, ordinal, interval, and ratio. Since statistical procedures are designed for specific kinds of data, we believe it is important to discuss each procedure separately, according to its level. SPSS can be used with all of these levels of data, as you will see.

DESCRIPTIVE AND INFERENTIAL STATISTICS

Statistics, like other courses of study, is multifaceted. It includes both descriptive and inferential processes. Descriptive statistics are methods to summarize and boil down the essence of a set of information so that it can be understood more readily and from different vantage points. We live in a world that is bombarded with data; descriptive statistical techniques are ways of making sense of it. Using these straightforward methods reveals numerical and visual patterns in data that are not immediately apparent. Stated differently, these methods allow us to see the world as it is, not necessarily by common sense.

Inferential statistics are a different matter altogether. These methods allow you to make predictions about unknown values on the basis of small sets of sample values. In real life, we are presented with situations that cannot provide us with ...