Page 243 - Statistics for Dummies

Chapter 15
Commonly Used Hypothesis Tests:
Formulas and Examples
In This Chapter
▶ Breaking down commonly used hypothesis tests
▶ Calculating their test statistics
▶ Using the results to make informed decisions
rom product advertisements to media blitzes on recent medical break-
Fthroughs, you often run across claims made about one or more popula-
tions. For example, “We promise to deliver our packages in two days or less”
or “Two recent studies show that a high-fiber diet may reduce your risk of
colon cancer by 20%.” Whenever someone makes a claim (also called a null
hypothesis) about a population (such as all packages, or all adults) you can test
the claim by doing what statisticians call a hypothesis test.
A hypothesis test involves setting up your hypotheses (a claim and its alterna-
tive), selecting a sample (or samples), collecting data, calculating the rele-
vant statistics, and using those statistics to decide whether the claim is true.

In this chapter, I outline the formulas used for some of the most common
hypothesis tests, explain the necessary calculations, and walk you through
some examples.

If you need more background information on hypothesis testing (such as
setting up hypotheses, understanding test statistics, p-values, significance
levels, and type-1 and type-2 errors), just flip to Chapter 14. All the general
concepts of hypothesis testing are developed there. This chapter focuses on
their application.

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