CHAPTER

9

Hypothesis Tests
CONTENTS

9.4

POPULATION MEAN: σ UNKNOWN
One-Tailed Test
Two-Tailed Test
Summary and Practical Advice

9.5

POPULATION PROPORTION
Summary

9.6

HYPOTHESIS TESTING AND
DECISION MAKING

9.7

CALCULATING THE
PROBABILITY OF TYPE II
ERRORS

9.8

DETERMINING THE SAMPLE
SIZE FOR A HYPOTHESIS
TEST ABOUT A POPULATION
MEAN

STATISTICS IN PRACTICE:
JOHN MORRELL & COMPANY
9.1

DEVELOPING NULL AND
ALTERNATIVE HYPOTHESES
The Alternative Hypothesis as a
Research Hypothesis
The Null Hypothesis as an
Assumption to Be Challenged
Summary of Forms for Null and
Alternative Hypotheses

9.2

TYPE I AND TYPE II ERRORS

9.3

POPULATION MEAN: σ KNOWN
One-Tailed Test
Two-Tailed Test
Summary and Practical Advice
Relationship Between Interval
Estimation and Hypothesis
Testing

349

Statistics in Practice

STATISTICS

in PRACTICE

JOHN MORRELL & COMPANY*
CINCINNATI, OHIO

John Morrell & Company, which began in England in
1827, is considered the oldest continuously operating meat manufacturer in the United States. It is a wholly owned and independently managed subsidiary of
Smithfield Foods, Smithfield, Virginia. John Morrell &
Company offers an extensive product line of processed meats and fresh pork to consumers under 13 regional brands including John Morrell, E-Z-Cut, Tobin’s First
Prize, Dinner Bell, Hunter, Kretschmar, Rath, Rodeo,
Shenson, Farmers Hickory Brand, Iowa Quality, and
Peyton’s. Each regional brand enjoys high brand recognition and loyalty among consumers.
Market research at Morrell provides management with up-to-date information on the company’s various products and how the products compare with competing brands of similar products. A recent study compared a
Beef Pot Roast made by Morrell to similar beef products from two major competitors. In the three-product comparison test, a sample of consumers was used to indicate how the products rated in