1. In this lecture we will review basic statistical concepts.  
This lecture is written by Dr. Maria Correa-Prisant, Dept. of Microbiology, Pathology, Parasitology, College of Veterinary Medicine , North Carolina State University 
Original PowerPoint file of this lecture

2. Compared to clinical work, this is the way we get to know our client the "data set."

3. There are many different types of variables and it is important that we recognize them since different statistical analyses are needed.

4. These are pictoral representations of different distributions for continuous data.

5. You CANNOT use tests developed for continuous data with ordinal or nominal variables.

6. The mean, median, and mode coincide when you have normally distributed data.

7. Only for continuous data.

8. When the data are not normally distributed, the mean may not be the appropriate measure of central tendency.

9.
Descriptive statistics
From Wikipedia, the free encyclopedia

10. Dispersion of the data can be expressed using the standard deviation (SD) or percentiles. Use of SD when data are not normally distributed may be innappropriate.

11. 2 standard deviation (SD) are commonly used
2 standard deviation (SD) are commonly used. Mean and Standard Deviation

12. Simply divide the data into 100 pieces
Simply divide the data into 100 pieces. Percentiles are not dependent on the distribution of the data.

13. Data Display and Summary

14. Data Display and Summary

15. The mean of the means is obtained first
The mean of the means is obtained first. Then calculated the standard error (SE) of that mean of means.
Populations and samples

16. For categorical data you CANNOT calculate the mean
For categorical data you CANNOT calculate the mean. It does not make sense!

17. Drawing or setting up your data into R by C tables may help you to get a better feeling for the case.

18. With statistical tests we determine association. We do not "prove"
With statistical tests we determine association. We do not "prove". We say: we either do not have enough evidence or we do to reject the Ho.

19. Review Questions (Developed by the Supercourse team)
Describe different types of variables
Describe different types of data distribution
What is association and what is the relationship between association and causation?
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