《社会研究方法》艾尔巴比_英文ppt_Ch8

One-shot case study - single group of subjects is measured on a variable following experimental stimulus. One-group pretest-posttest design - adds a pre-test for the group, but lacks a control group. Static-group comparison - includes experimental and control group, but no pre-test.
Question

_____________ groups are groups of subjects to whom an experimental stimulus is administered. A. control B. experimental C. purposive D. triad
One-Shot Case Study

A man who exercises is observed to be in trim shape.
One-Group Pretest-Posttest Design

An overweight man who exercises is later observed to be in trim shape
Question

______________ is a technique for assigning experimental subjects to experimental and control groups randomly. A. nonprobability analyses B. matching C. randomization D. none of these choices
Part Three
Modes of Observation
Chapter 8
Experiments
Chapter Outline


Introduction Topics Appropriate to Experiments The Classical Experiment Selecting Subjects


Probability sampling Randomization Matching
Randomization and Matching


May not know which variables will be relevant for matching process. MosΒιβλιοθήκη Baidu statistics used to analyze results assume randomization. Randomization only makes sense if you have a large pool of subjects.
Chapter Outline


Variations on Experimental Designs An Illustration of Experimentation Alternate Experimental Settings Strengths and Weaknesses of the Experimental Method
Answer: C

Randomization is a technique for assigning experimental subjects to experimental and control groups randomly.
Open Matrix Illustration
Preexperimental Research Designs
Topics Appropriate to Experiments


Projects with limited and well-defined concepts. Projects that are exploratory rather than descriptive. Studies of small group interaction.
Static-Group Comparison

A man who exercises is observed to be in trim shape while one who doesn’t is observed to be overweight.
Question

In a one-group pretest-posttest design, what is lacking? A. EPSEM B. an experimental group C. a control group D. none of these choices
Experimental and Control Groups


Must be as similar as possible. Control group represents what the experimental group would have been like had it not been exposed to the stimulus.
Answer: C

In a one-group pretest-posttest design, a control group is lacking.
Sources of Internal Invalidity



Historical events may occur during the course of the experiment. Maturation of the subjects. Testing and retesting can influence behavior. Instrumentation
Answer: D

In the simplest experimental design, subjects are measured in terms of a dependent variable exposed to an independent variable.
Subjects


Experimental group - A group of subjects to whom an experimental stimulus is administered. Control group - A group of subjects to whom no experimental stimulus is administered and who resemble the experimental group in all other respects.
Solomon Four-group Design
Solomon Four-group Design

Expected Findings In Group 1, posttest prejudice should be less than pretest prejudice. In Group 2, prejudice should be the same in the pretest and the posttest. The Group 1 posttest should show less prejudice than the Group 2 posttest does. The Group 3 posttest should show less prejudice than the Group 4 posttest does.
Question

What is the basic difference between the classical design and the Solomon four-group design? A. There is no difference. B. The Solomon four-group design repeats the classical design but adds groups that are not pretested. C. The Solomon four-group design repeats the classical design but adds groups that are not posttested.
Components of Experiments
Three Pairs Independent and dependent variables Pretesting and posttesting Experimental and control groups
Question

In the simplest experimental design, subjects are measured in terms of a _________ variable exposed to an _________ variable. A. pretested; posttested B. fluid; static C. independent; dependent D. dependent; independent
Limiting External Invalidity


Solomon four-group design Posttest-only control group design
The Classical Experiment
Solomon Four-group Design
Four groups of subjects, assigned randomly: Groups 1 and 2 are the control and experimental group. Group 3 does not have the pre-test. Group 4 is only posttested.
Sources of Internal Invalidity



Statistical regression of subjects starting out in extreme positions. Selection biases. Experimental mortality - subjects drop out of the study before it's completed. Demoralized control group subjects.
Double-blind Experiment

An experimental design in which neither the subjects nor the experimenters know which is the experimental group and which is the control.
Answer: B

The basic difference between the classical design and the Solomon fourgroup design is that the Solomon fourgroup design repeats the classical design but adds groups that are not pretested.
Answer: B
• Experimental groups are groups of subjects to whom an experimental stimulus is administered.
Diagram of Basic Experimental Design
Selecting Subjects