Better Business Decisions from Data

CHAPTER 10

Comparisons with Numerical Data

Are Today’s Chocolate Bars Smaller Than Yesterday’s?

Once a numerical sample or population has been characterized in a quantifiable way, as shown in Chapter 7, it can be compared with others to seek differences or similarities. This chapter explains what can be learned from single values, pairs of values, pairs of samples, and sets of samples. In each case, the null hypothesis, that no difference is evidenced, is set up; and, by calculating the appropriate test statistic, it is established whether the null hypothesis should be accepted or not.

Single Value

The null hypothesis is that a single value could have come from a given population. An example might be to investigate whether a bar of chocolate ...