商业研究方法014(免费阅读).ppt

Chapter FourteenEXPERIMENTATION Variables in Experiments Independent variables Dependent variables Advantages of an Experiment? Researcher’s ability to manipulate the independent variable Contamination from extraneous variables can be controlled more efficiently Convenience Cost Replication Disadvantages of Experiments Artificiality of the laboratory Generalization from nonprobability samples Larger budgets needed Restricted to problems of the present or immediate future Ethical limits to manipulation of people Experimentation Process Select relevant variables Specify the treatment levels Control the experimental environment Choose the experimental design Select and assign the participants Pilot-test, revise, and test Analyze the data Ways to Assign Subjects Random Assignment Matching Assignment Quota matrix Does a Measure Accomplish What it Claims? Internal validity External validity Threats to Internal Validity History Maturation Testing Instrumentation Threats to External Validity The Reactivity of Testing on X Interaction of Selection and X Other Biasing Effects on X Artificial setting of testing Respondents knowledge of testing Experimental Designs Preexperimental designs True experimental designs Field experiments Design Symbols X the introduction of an experimental stimulus to the participant 0 a measure or observation activity R an indication that sample units have been randomly assigned Preexperimental Designs One-shot case study One-group pretest-posttest design Static group comparison True Experimental Designs Pretest-posttest control group design Posttest-only control group design Operational Extensions of True Designs Completely randomized designs Randomized block design Latin square Factorial design Covariance analysis Field Experiments: Quasi- or Semi-Experiments Non Equivalent Control Group Design Separate Sample Pretest-Posttest Design Group Time Series Design 14-* McGraw-Hill/Irwin ? 2003 The McGraw-Hill Companies, Inc