Statistics Workbook For Dummies with Online Practice, 2nd Edition

Chapter 10

Making Sense of Margin of Error

IN THIS CHAPTER

Discovering the three main components of margin of error

Knowing how the components affect the size of the margin

Computing the margin of error for means and proportions

Accurately interpreting margin of error

Margin of error is a critical element for understanding confidence intervals, a heavyweight topic on introductory statistics syllabi. Although the calculations are very important, you also need to look at the components of margin of error and how they each play a role in what the value of the margin of error is. Another important element is knowing what margin of error actually measures. Looks can be deceiving. This chapter goes over the basics of margin of error; Chapter 11 focuses on actually calculating confidence intervals, based on these margin-of-error ideas, and Chapter 12 deals with interpreting your confidence intervals properly.

Reviewing Margin of Error

One of the main caveats of sample results is that they vary from sample to sample, so you shouldn’t report statistical results without also including the ...