Statistics For Dummies®, 2nd Edition

Chapter 14

Claims, Tests, and Conclusions

In This Chapter

• Testing other people's claims
• Using hypothesis tests to weigh evidence and make decisions
• Recognizing that your conclusions could be wrong

You hear claims involving statistics all the time; the media has no shortage of them:

• Twenty-five percent of all women in the United States have varicose veins. (Wow, are some claims better left unsaid, or what?)
• Cigarette use in the U.S. continues to drop, with the percentage of all American smokers decreasing by about 2% per year over the last ten years.
• A 6-month-old baby sleeps an average of 14 to 15 hours in a 24-hour period. (Yeah, right!)
• A name-brand ready-mix pie takes only 5 minutes to make.

In today's age of information (and big money), a great deal rides on being able to back up your claims. Companies that say their products are better than the leading brand had better be able to prove it, or they could face lawsuits. Drugs that are approved by the FDA have to show strong evidence that their products actually work without producing life-threatening side effects. Manufacturers have to make sure their products are being produced according to specifications to avoid recalls, customer complaints, and loss of business.

Although many claims are backed up by solid scientific (and statistically sound) research, others are not. In this chapter, you find out how to use statistics to investigate whether a claim is actually valid and get the lowdown on the process that researchers ...