404 ch 2

Chapter 2: Epidemiology and Data 

1. What are types of data and measurement scales used in Epidemiology?

   1. Types of data: 

      1. Qualitative data: does not have numerical values or rankings (ex: marital status and sex) 

      2. Quantitative data: reported as numerical quantities 

   2. Measurement scales: 

      1. Stevens measurement scales: 

         1. Nominal (name)

         2. Ordinal (order)

         3. Interval (continuous data) 

         4. Ratio (intervals w/ true zero data point)

2. How can Epidemiologic data be presented graphically in meaningful ways?

   1. Bar chart: shows the frequency of cases for categories of discrete variable

      1. Ex: qualitative, yes or no variables 

   2. Line graph: used to display trends 

      1. Ex: time trends 

   3. Pie chart: shows the proportion of cases according to several categories 

3. What are measures of central tendency and bivariate associations?

   1. Central tendency: 

      1. Mode: number that occurs more frequently in a set of distribution 

      2. Median: middle point of a set of numbers  

      3. Mean: mean or average 

   2. Bivariate associations: relationships b/w 2 variables (related not casual) 

      1. Scatter plot: 

      2. Pearson correlation coefficient 

      3. Contingency tables: 

4. What are various types of data used in Epidemiology?

5. How are parameter estimates used in Epidemiology?

   1. Measurable attribute of a population (ex: average age)

6. Describe fundamental concepts of populations, samples, and methods

   1. Population:  collection of people who share common observable characteristics 

   2. Samples: subgroup that has been selected from the population

   3. Methods: random and nonrandom 

7. Identify and describe types of Epidemiologic variables

   1. Discrete variable: discrete countable data like household size 

   2. Continuous variable: continuous data like heart rate, blood sugar levels 

8. Distinguish between methods for displaying data in Epidemiology

   1. Bar chart: frequency of cases for categories 

   2. Life graph: displays trends 

   3. Pie chart: proportion of cases to several categories 

   4. Scatter plot: 

   5. Contingency table: demonstrates associations 

9. Describe classifications and possible relationships between variables in Epidemiology

   1. Qualitative: no numerical values 

   2. Quantitative: numerical 

10. Describe various methods for sampling data

    1. Random (simple and stratified)

       1. Unbiased 

    2. Nonrandom (convenience, systematic, clustering)