Types of Research

1. Types of Research Experimental Research

2. Experimental Research • Traditional type of research • Only research performed in the sciences • Future-focused • Involves manipulation of the independent variable(s)

3. Steps to Experimental Research 1. State the research problem 2. Specify the independent variable(s) and levels 3. Specify the dependent variable(s) 4. Determine the availability of measures of the dependent variable 5. Identify the potential of intervening (extraneous) variables 6. State the research hypotheses 7. Design the experiment

4. Steps to Experimental Research 8. Conduct the study as planned 9. Analyze the data 10. Prepare the research report

5. The Effect of Frequency and Time of Training on Cardiovascular Endurance • Independent variable(s)? • Dependent variable?

6. Independent Variables • Frequency = Number of training days per week Levels: 3 days/week 5 days/week • Time = Minutes per day Levels: 20 minutes/day 40 minutes/day 60 minutes/day • 2 x 3 (Frequency x Time) Factorial Design

7. Dependent Variable • Cardiovascular Conditioning • Operational Definition?

8. Research Hypotheses? Main Effects • Frequency • Time Interaction Effect • Frequency x Time

9. Research Design Time Frequency

10. Results (12 Minute Run – Laps Completed) Time Frequency

11. ResultsBar Graph

12. ResultsLine Graph – Significant Main Effects

13. ResultsLine Graph – Interaction Effect

14. Internal Validity • Were the changes in the dependent variable the result of the independent variable or were they due to something else?

15. Selection Experimental Mortality Interaction of Selection and Maturation or History History Maturation Testing Instrumentation Statistical Regression Threats to Internal Validity

16. External Validity • Can the findings be generalized beyond the subjects or settings studied in the experiment?

17. Threats to External Validity • Reactive or interactive effects of testing • Pre-testing may change the approach to the treatment • Interaction of selection bias & experimental treatment • Group characteristics affect the effectiveness of the treatment • Reactive effects of experimental settings • Lab is different than the real world environment • Multiple-treatment interference • Previous treatments can affect future treatments

18. Types of Experimental Designs • Pre-experimental • Quasi-experimental • True experimental

19. Research Design Notation • R = Random assignment • T = Treatment • O = Observation

20. Pre-Experimental • Primitive designs • Designed only to show the effects of a treatment • Do not control for internal validity

21. Pre-Experimental • No random assignment of subjects • One-shot Study • Treatment given then test administered T O1 • One-group Pretest-Posttest design • Test administered then treatment then the same test O1 T O2 • Static Group comparison • Treatment to one group then test them • Second group is tested with the same test (no treatment) T O1 O2

22. Quasi-Experimental • Better than pre-experimental • When subjects cannot be randomly selected or randomly assigned to treatment groups • Controls some threats to internal validity

23. Quasi-Experimental Designs • Promote external validity & maintain internal validity 1. Time series design O1 O2 O3 O4 T O5 O6 O7 O8 2. Reversal design O1 O2 T1 O3 O4 T2 O5 O6 3. Non-equivalent control group O1 T O2 O3 O4

24. True Experimental • Recommended • Random selection of subjects from the population • Random assignment of subjects to treatment groups • Controls threats to internal and external validity

25. True Experimental Designs • Better control of research short-comings • Randomized-groups design • Random selection then treat groups then test all groups R T1 O1 R T2 O2 R O3 • Pretest-posttest randomized-groups design • Random selection test all groups, treat some groups then test all groups again R O1 T O2 R O3 O4

26. True Experimental Designs 3. Solomon four-group design • Controls almost all threats to internal validity • Controls the major threats to external validity R O1 T O2 R O3 O4 R T O5 R O6

27. Methods of Control • Randomization: Random selection from the population and random assignment to treatment groups • Physical Manipulation: The researcher physically controls all aspects of the subjects’ environment • Selective Manipulation: To increase the likelihood that the treatment groups are similar at the outset * Matched pairs * Block designs * Counter-balanced design

28. Methods of Control • Statistical Techniques: Some statistical procedures can manipulate the data to control for group differences at the beginning of the experiment * Analysis of Covariance (ANCOVA)

29. Sources of Error • Hawthorne Effect • Placebo Effect • “John Henry” (Avis) Effect • Rating Effect • Experimenter Bias Effect • Subject-Researcher Interaction Effect • Post Hoc Error (cockroach story)

30. Uncontrolled Threats to Internal Validity • Randomization does not help with the following: • Reactive or Interactive effects of testing • Must eliminate the pretest • Test reliability and validity • Calibrated equipment, objective evaluation, & accuracy • Experimental mortality • Not much you can do if they want to quit

31. Controlling Internal Validity Threats • Randomization • History, maturation, statistical regression, selection errors • Placebos, Blind, & Double-Blind setups • Hawthorne effect • Subjects change due to receiving attention • Expectancy effect • Select groups are expected to do better • Halo effect • “Brownie” points, previous scoring taint future scoring • Avis effect • Control subjects try harder because they are not in the experimental group

32. Controlling External Validity Threats • Randomization is a major tool! • Other important processes • Selecting the subjects • Carefully selected treatments • Experimental situations • Tests which represent larger populations • Ecological Validity • Generalizing the situation • “Real-World” environment • Practice versus Meet performance!