1. Research Designs Quantitative studies

2. Experimental Research One important chch. Is that the researcher is an active agent rather than passive What are the main chch for true experiment? 1. Manipulation: doing something

3. Cont…. Chch of true experiment 2. Randomization: placement of subject in a random base Random assignment: every subject has an equal chance to participate in the research study

4. Matching. Tables random numbers Cluster randomization Stratified randomization

5. Cont…. Chch of true experiment 3. Control: acquired by manipulating, randomizing and planning Control group vs. experimental group Treatment and intervention are used interchangeably

6. Experimental Designs Basic experimental designs: 1. After only design (or posttest design) 2. Before-after test design (pretest posttest design) 3. Sometimes we call: Before test as baseline measure After test as outcome measures

7. Solomon four-group design (2 exp and 2 control groups) Group Data collection BeforeAfter Exp with pretest xx Exp without pretest x Control with pretest xX Control without pretest x

8. Factorial Design Multiple hypothesis in a single experiment Time 1 Time 2 Time 3 A1B1A1B2 A2B2 A1B3A2B2 Factor A Factor B

9. Repeated Measures: exposure of the one subject to more than one experimental treatment Randomized Clinical Trials: it involves testing a clinical treatment. May be before only or before after.

10. Advantages of experimental Designs 1. It is the most powerful to test cause-effect relationships 2. Through control, alternative explanations can be ruled out.

11. Disadvantages of experimental designs 1. Constrains such as.. 2. Artificiality 3. Hawthorne effect 4. Subject to limitation in application in the real world

12. Quasi-experimental designs Nonequivalent control group designs: an experimental group and two or more groups of subjects. o 1 x o 2 o 1 o 2

13. Collecting data more than thon one time and during which interventions are imposed. O O O X O O O X OOO Time Series:

14. Adv ns. Disadv. Of Quasi-experimental Advantages: 1. Flexibility. 2. Practicality 3. Generalizability Disadvantage : 1. Plausibility