The subject of statistics involves the study of how to collect, summarize, and interpret data. Data are numerical facts and figures from which conclusions can be drawn. Such conclusions are important to the decision-making processes of many professions and organizations. For example, government officials use conclusions drawn from the latest data on unemployment and inflation to make policy decisions. Financial planners use recent trends in stock market prices to make investment decisions. Businesses decide which products to develop and market by using data that reveal consumer preferences. Production supervisors use manufacturing data to evaluate, control, and improve product quality. Politicians rely on data from public opinion polls to formulate legislation and to devise campaign strategies. Physicians and hospitals use data on the effectiveness of drugs and surgical procedures to provide patients with the best possible treatment.

In this chapter we begin to see how we collect and analyze data. As we proceed through the chapter, we introduce several case studies. These case studies (and others to be introduced later) are revisited throughout later chapters as we learn the statistical methods needed to analyze the cases. Briefly, we will begin to study four cases:

The Cell Phone Case. A bank estimates its cellular phone costs and decides whether to outsource management of its wireless resources by studying the calling patterns of its employees.

The Marketing Research Case. A bottling company investigates consumer reaction to a new bottle design for one of its popular soft drinks.

The Coffee Temperature Case. A fast-food restaurant studies and monitors the temperature of the coffee it serves.

The Car Mileage Case. To determine if it qualifies for a federal tax credit based on fuel economy, an automaker studies the gas mileage of its new midsize model.