1. Statistical Inference & Hypothesis Testing Chapter 10

2. Statistical Inference The drawing of conclusions by the use of quantitative or qualitative information

3. HOW ???

4. Reasoning… Inductive –Finding valid answers from examination of the data Deductive –Finding valid answers using mathematic applications against the data

5. Example… Inductive –Studying relationship between two types of data Ex: The rate of hypertension among smokers Deductive –Proving or disproving of a hypothesis Ex: Smoking causes high blood pressure

6. Mathematics Versus Statistics An equation may be written using the same formula and have different applications in math or statistics Consider the equation: y = mx + b –Mathematically: Formula for defining a straight line in geometry –Statistically: Formula for simple regression analysis

7. The Hypotheses of Statistics Null Hypothesis –States there is no difference between the means of the two compared groups being studied Alternative Hypothesis –States that there is a true difference between the means of the two compared groups being studied

8. Refer to Page 158; Table 10-1 This list simplifies the steps to testing a null hypothesis for Statistical Significance

9. Establishing a Alpha Level The Rules Generally p (false positive) =.05 or 5% Leads to a 95% confidence interval of arriving at the right hypothesis

10. Test of Statistical Significance Obtain a “p” value for the data –Example: Standard Deviation Confidence Intervals Mean, Mode and Median Student t-test (1 or 2 tailed) Compare the p values (answers) to the alpha level Does this answer satisfy the null or alternative hypothesis?

11. Example – Hypothesis Development H 0 : Men who eat pizza three times a week will gain ten pounds over the three week period (Alternativel Hypothesis) H 1 : Men who eat pizza three times a week will not gain ten pounds over the three week period (Null Hypothesis)

12. Consider the data… SubjectsPRE WtPOST WTDifference 112813810 210011010 311012010 414541-4 52012154 62002011 7198196-2 81571570 9300289-11 101941951 Mean173176

13. Well… Do you accept or reject the null hypothesis Do you accept or reject the alternative hypothesis

14. Reject the null hypothesis Accept the alternative hypothesis

15. Student t-Tests Most commonly used statistical test in medicine Compares means of the variables of two research samples (groups) May be used in research groups which differ –i.e. Male/Female; dogs/cats May be 1 or 2 tailed (which affects interpretation)

16. The “p” of the “t” In regards to the “t” test and the use of “p” –If “t” is large (means of samples) then “p” is small (percentage of error) and the difference is regarded as real (i.e. believable) –If “p” is large (larger than 5%) then the difference is not real (unrealistic or unbelievable)

17. CHAPTER 14 INTRODUCTION TO PREVENTATIVE MEDICINE

18. Preventive Medicine Promotes general health Prevention of disease Application of epidemiological concepts –Aid in prevention –Aid in promotion

19. Health A state of complete physical, mental and social well-being, not merely the absence of disease or infirmity -World Health Organization

20. STRESS Good –Known as Eustress Exercise Infant stimulation Bad –Known as distress Mal-adaption Environmental

21. Measures of Health Status Mortality Data Life Expectancy Quality of Adjusted Life Years (QALY)

22. Natural History of Disease Latent: –Also known as: “hidden” –Offers a window of opportunity for early detection Symptomatic: –Produces clinical manifestations that are measurable Tertiary: –Disease progression in the absence of intervention

23. Levels of Prevention Primary: –Eliminate the cause of disease –Example: Vaccinations Secondary: –Interrupt the disease process prior to symptoms occuring –Example: Medication or Surgical intervention Tertiary: –Limiting physical and social consequences of symptomatic disease –Example: Rehabilitation/therapy

24. QUESTIONS

25. Chapter 15 – Health Promotion Nutritional Factors – How important is this factor?

26. Is nutrition a concern in the US or is it “just a Third World problem”

27. How can nutritional issues be addressed within the scope of preventive medicine.

28. What is the difference between Environmental and Occupational health promotion?

29. Explore routes of exposure to environmental hazards. How dangerous are these? What are some sources?

30. Behavioral factors: How do we promote prevention here. Someone cite an example and let us discuss briefly?

31. 1 Minute Open Forum