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Unformatted text preview: 1 Chapter 4: Gathering Data Read Chapter 5 1. Population versus Sample 2. Types of Studies: Experimental and Observational 3. Comparing Experimental and Observational Studies Learning Objectives: More Good Ways and Poor Ways to Sample? 1. Sampling Frame & Sampling Design 2. Simple Random Sample (SRS) 3. Random number table 4. Margin of Error 5. Convenience Samples 6. Types of Bias in Sample Surveys What Are Good Ways and Poor Ways to Experiment? 1. Identify the elements of an experiment 2. Experiments 3. 3 Components of a good experiment 4. Blinding the Study 5. Define Statistical Significance 6. Generalizing Results of the Study 3 Components of a Good Experiment Control/Comparison group: allows the researcher to analyze the effectiveness of the primary treatment Randomization: eliminates possible researcher bias, balances the comparison groups on known as well as on lurking variables Replication: allows us to attribute observed effects to the treatments rather than ordinary variability Even More Ways to Conduct Experimental and Observational Studies 1. Sample Surveys: Other Random Sampling Designs 2. Types of Observational Studies: Prospective and Retrospective 3. Multifactor Experiment 4. Randomized block design 2 Sample Surveys: Random Sampling Designs It is not always possible to conduct an experiment so it is necessary to have well designed, informative studies that are not experimental, e.g., sample surveys that use randomization Simple Random Sampling Cluster Sampling Stratified Random Sampling Sample Surveys: Cluster Random Sample Cluster Random Sample Steps: Divide the population into a large number of clusters , such as city blocks, organizations, etc....
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This note was uploaded on 01/09/2010 for the course ILRST 2100 at Cornell University (Engineering School).