Why It Matters: Descriptive Statistics

Why should you understand how to summarize collected data both graphically and numerically?

Before we begin Descriptive Statistics, let’s see how the new ideas in this module relate to what we learned in the previous module, Sampling and Data.

Recall the big picture: Data is gathered from a sample of the population to investigate the answer to a research question. The data is organized and graphs and numerical summaries are created. This is exploratory data analysis. Using the data and probability, inferential statistics is used to draw conclusions about the population.

Step 2 of "The Big Picture": Exploratory Data Analysis. "The Big Picture" summarizes the steps in the statistical investigation. These steps are as follows: Step 1: Producing Data (collecting a sample from the population), Step 2: Exploratory Data Analysis, Step 3: Probability, and Step 4: Inference.

The previous module focused on data collection methods, well-designed experiments, and basic concepts related to organizing different types of data. In this module, we focus on exploratory data analysis. Specifically we will be discussing measures of location of data, measures of center of data and measures of spread of data. A variety of graphical methods will be explored with an emphasis on histograms and box plots.