R All-in-One For Dummies

Chapter 4

Meeting Standards and Standings

IN THIS CHAPTER

Standardizing scores

Making comparisons

Working with ranks in files

Rolling in the percentiles

In my left hand I hold 100 Philippine pesos. In my right, I hold 1,000 Colombian pesos. Which is worth more? Both are called pesos, right? So shouldn’t the 1,000 be greater than the 100? Not necessarily. Peso is just a coincidence of names. Each one comes from a different country, and each country has its own economy.

To compare the two amounts of money, you have to convert each currency into a standard unit. The most intuitive standard for US residents is our own currency. How much is each amount worth in dollars and cents? As I write this chapter, 100 Philippine pesos are worth $1.82. One thousand Colombian pesos are worth 24 cents.

So, when we compare numbers, context is important. To make valid comparisons across contexts, we often have to convert numbers into standard units. In this chapter, I show you how to use statistics to do just that. Standard units show you where a score stands in relation to other scores within ...