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Objectives. Overview of Biostatistical Terms and ConceptsApplication of Statistical Tests. Why Use Statistics?. Descriptive Statisticsidentify patterns leads to hypothesis generatingInferential Statisticsdistinguish true differences from random variationallows hypothesis testing. Why Use Statistics?.
                
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1. BASIC  BIOSTATISTICS Diane Flynn, LTC, MC
Colin Greene, LTC, MC 
2. Objectives 
Overview of Biostatistical 
	Terms and Concepts
Application of Statistical Tests 
3. Why Use Statistics? Descriptive Statistics
identify patterns 
leads to hypothesis generating
Inferential Statistics
distinguish true differences from 
	random variation
allows hypothesis testing 
4. Why Use Statistics?      
5. Types of Data Numerical 
Continuous
Discrete 
Categorical
Ordinal 
Nominal
 
6. Descriptive Statistics 
Identifies patterns in the data
Identifies outliers
Guides choice of statistical test 
7. Percentage of Specimens Testing Positive for RSV 
8. Descriptive Statistics 
9. Describing the Data with Numbers 
Measures of Central Tendency
MEAN -- average
MEDIAN -- middle value
MODE -- most frequently observed 				     value(s) 
10. Distribution of Course Grades 
11. Describing the Data with Numbers 
Measures of Dispersion
RANGE 
STANDARD DEVIATION
SKEWNESS
  
12. Measures of Dispersion RANGE 
highest to lowest values
STANDARD DEVIATION
how closely do values cluster around the mean value
SKEWNESS
refers to symmetry of curve 
13. Measures of Dispersion RANGE 
highest to lowest values
STANDARD DEVIATION
how closely do values cluster around the mean value
SKEWNESS
refers to symmetry of curve 
14. Standard Deviation 
15. Measures of Dispersion RANGE 
highest to lowest values
STANDARD DEVIATION
how closely do values cluster around the mean value
SKEWNESS
refers to symmetry of curve 
16. Skewness 
17. The Normal Distribution Mean = median = mode
Skew is zero
68% of values fall between 1 SD
95% of values fall between 2 SDs 
18. Inferential Statistics 
   Used to determine the likelihood that a conclusion based on data from a sample is true 
19. Terms 
p value: the probability that an observed difference could have occurred by chance
 
20. Hypertension Trial 
21. Terms 
confidence interval:
The range of values we can be reasonably certain includes the true value.
 
22. 30 Day % Mortality  
23. 95% Confidence Intervals 
24. Types of Errors 
25. What Test Do I Use? 1.  What type of data?
2.  How many samples?
3.  Are the data normally distributed?
4.  What is the sample size?