Lesson Two
Lesson
Introduction <br> In the previous lesson, you learned about sample surveys and bias. In this lesson, you’ll learn about another kind of data source: the observational study. <br> In this lesson, you will: Learn considerations for working with your data. Learn that it’s not enough simply to look at a change in mean or median; you really need to look at the spread as well. Ideally, you study the entire distribution. Make sure that the data you plot reflects what you’re actually interested in. For example, in an education study, you have to decide what’s more important: students’ final score or the amount they improve. Design your study carefully to get less-biased data. For example, you might decide to choose your sample randomly, and you may measure your data using “blind” study techniques.