1. Statistics Experimental Design

2. EXPERIMENTAL DESIGN
IN-CLASS PROBLEM
What is an experiment?

3. What is an experiment? a controlled study
EXPERIMENTAL DESIGN
IN-CLASS PROBLEM
What is an experiment? a controlled study

4. EXPERIMENTAL DESIGN
IN-CLASS PROBLEM
What is an experiment? a controlled study goal: to determine the effect of factors on the results

5. Design of Experiments
Factors: explanatory variables that have an effect on the experimental results

6. Design of Experiments
Experimental unit: a member of the sample “subject”

7. Design of Experiments
Control groups – untreated subjects let you compare “treated” vs “untreated” subjects

8. Design of Experiments
Placebo – often used in drug studies counteracts the “I’m taking something so I’ll get better” psychological effect

9. Design of Experiments
Steps: Identify the problem Determine factors affecting the result Determine the sample size Control or randomize factor levels Conduct the experiment Test the claim

10. Design of Experiments
Types of Experiments: completely randomized sample members are randomly assigned to treatments

11. Design of Experiments
Blinding: single blind – the subject does not know the treatment double blind – neither the subject nor the researcher knows the

12. Design of Experiments
Types of experiments: matched pairs members of the sample are paired when assigned to treatments

13. Design of Experiments
Examples: before/after twins litter mates spouses same location same time

14. Questions?

15. Experimental Design
How to design a research study

16. Experimental Design
Guidelines for designing a study:

17. Experimental Design
Guidelines for designing a study: 1. Identify the population and variables of interest

18. Experimental Design
Guidelines for designing a study: 2. Develop a detailed plan for collecting data

19. Experimental Design Guidelines for designing a study:
3. Collect the data using any of the following methods:
i. Doing an observational study
ii. Performing an experiment
iii. Using a simulation
iv. Using a survey

20. Experimental Design
Guidelines for designing a study: 4. Graph your data (or the statistics demons will get you…)
Thanks to Jonathan Bellamy
for the stupendous
Stat Demon drawing !

21. Experimental Design
Guidelines for designing a study: 5. Interpret the data and draw conclusions about the population

22. Experimental Design
Guidelines for designing a study: 6. Identify any possible errors

23. Mr Pólya’s Method: Understand the problem 2) Plan! 3) Do it!
Experimental Design
IN-CLASS PROBLEM
Mr Pólya’s Method:
Understand the
problem
2) Plan!
3) Do it!
4) Look back
George Pólya

24. Questions?