-Qualitative -vs- Quantitative Data: Later in the text we will conduct various statistical tests about qualitative and quantitative characteristics of various populations. For qualitative data we usually use proportions (percentages) and for quantitative data we usually use means (averages).

Qualitative Data and Proportions: Suppose you want to compare the popularity of red cars versus black cars at various car dealers. How would you use percentages to make such a comparison?

Quantitative Data and Means: Suppose you want to compare the gas mileage between American- made cars and German-made cars. How would you use averages to make such a comparison?

- Lowest Prices in Town: Two grocery stores claim to have the lowest prices in town. How would you verify which one actually has the lowest prices?

Percentages of Percentages: According to a study by the U.S. Center for Disease Control (CDC) the flu rate in people who do not get the flu shot is 2.73% and the rate for people who do get the flu shot is 1.18%. They claim the flu shot is 60% effective. How did they arrive at this number?