As you have already learned in this book, decision makers use Statistical methods to help analyze data and communicate results. Every day, somewhere, someone misuses these techniques either by accident or intentional choice. Identifying and preventing such misuses of statistics is an important responsibility for all managers. The Digital Cases give you the practice you need to help develop the skills necessary for this important task.

Each chapter’s Digital Case tests your understanding of how to apply an important statistical concept taught in the chapter. As in many business situations, not all of the information you encounter will be relevant to your task, and you may occasionally discover conflicting information that you have to resolve in order to complete the case. 

To assist your learning, each Digital Case begins with a learning objective and a summary of the problem or issue at hand. Each case directs you to the information necessary to reach your own conclusions and to answer the case questions. Many cases, such as the sample case worked out next, extend a chapter’s Using Statistics scenario. You can download digital case files for later use or retrieve them online from a MyStatLab course for this book, as explained in Appendix C.

To illustrate learning with a Digital Case, open the Digital Case file Whitney Wireless.pdf that contains summary information about the Whitney Wireless business. Recall from the Using Statistics scenario for this chapter that Good Tunes & More (GT&M) is a retailer seeking to expand by purchasing Whitney Wireless, a small chain that sells mobile media devices. Apparently, from the claim on the title page, this business is celebrating its “best sales year ever.”

Review the Who We Are, What We Do, and What We Plan to Do sections on the second page. Do these sections contain any useful information? What questions does this passage raise? Did you notice that while many facts are presented, no data that would support the claim of “best sales year ever” are presented? And were those mobile “mobilemobiles” used solely for promotion? Or did they generate any sales? Do you think that a talk-with-your-mouth-full event, however novel, would be a success?

Continue to the third page and the Our Best Sales Year Ever! section. How would you support such a claim? With a table of numbers? Remarks attributed to a knowledgeable source? Whitney Wireless has used a chart to present “two years ago” and “latest twelve months” sales data by category. Are there any problems with what the company has done? Absolutely!

First, note that there are no scales for the symbols used, so you cannot know what the actual sales volumes are. In fact, as you will learn in Section 2.7, charts that incorporate icons as shown on the third page are considered examples of chartjunk and would never be used by people seeking to properly visualize data. The use of chartjunk symbols creates the impression that unit sales data are being presented. If the data are unit sales, does such data best support the claim being made, or would something else, such as dollar volumes, be a better indicator of sales at the retailer?

For the moment, let’s assume that unit sales are being visualized. What are you to make of the second row, in which the three icons on the right side are much wider than the three on the left? Does that row represent a newer (wider) model being sold or a greater sales volume? Examine the fourth row. Does that row represent a decline in sales or an increase? (Do two partial icons represent more than one whole icon?) As for the fifth row, what are we to think? Is a black icon worth more than a red icon or vice versa?

At least the third row seems to tell some sort of tale of increased sales, and the sixth row tells a tale of constant sales. But what is the “story” about the seventh row? There, the partial icon is so small that we have no idea what product category the icon represents.

Perhaps a more serious issue is those curious chart labels. “Latest twelve months” is ambiguous; it could include months from the current year as well as months from one year ago and therefore may not be an equivalent time period to “two years ago.” But the business was established in 2001, and the claim being made is “best sales year ever,’ so why hasn’t management included sales figures for every year?

Are the Whitney Wireless managers hiding something, or are they just unaware of the proper use of statistics? Either way, they have failed to properly organize and visualize their data and therefore have failed to communicate a vital aspect of their story.

In subsequent Digital Cases, you will be asked to provide this type of analysis, using the open ended case questions as your guide. Not all the cases are as straightforward as this example, and some cases include perfectly appropriate applications of statistical methods.