Statistics Essentials For Dummies

Chapter 8

Hypothesis Tests

IN THIS CHAPTER

General ideas for a hypothesis test

Type I and Type II errors in testing

Specific hypothesis tests for one or two population means or proportions

Hypothesis testing is a statistician’s way of trying to confirm or deny a claim about a population using data from a sample. For example, you might read on the Internet that the average price of a home in your city is $150,000 and wonder if that number is true for the whole city. Or you hear that 65% of all Americans are in favor of a smoking ban in public places — is this a credible result? In this chapter, I give you the big picture of hypothesis testing as well the details for hypothesis tests for one or two means or proportions. And I examine possible errors that can occur in the process.

Doing a Hypothesis Test

A hypothesis test is a statistical procedure that’s designed to test a claim. Typically, the claim is being made about a population parameter (one number that characterizes the entire population). Because parameters tend to be unknown quantities, everyone wants to make claims about what their values may be. For example, the claim that 25% (or 0.25) of all women have varicose veins ...