Research Design & Scales of Measurement
 

Research process:

1) ask research question(s)

2) develop hypotheses

3) collect the data

4) analyze the data

5) evaluate the hypotheses
 

Asking research questions


Developing hypotheses


Collecting data
 

Populations, samples, and sampling:

Population Sample Sample type
pregnant women  every other pregnant woman at 3 Tacoma clinics  
Fortune 500 Fortune 500 cos. in WA  
adults in U.S. random sample of adults in households w/ telephones  
Superfund sites 65 largest sites in U.S.  

  Variables and measurement


Scales/levels of measurement


nominal - values indicate qualitatively different kinds

  • quantitative var. = ordinal or interval var.

  •  

     

    ordinal - values indicate ordered categories

    interval/ratio - degree of distance/difference between values can be specified


    Warning: be careful w/ numeric coding of nominal and ordinal scale data!
     
     

    Scales of measurement form a hierarchy:

    interval

    ordinal

    nominal



     
    scale key feature comparisons betw. values
    interval distance different? which larger? how much larger?
    ordinal order different? which larger?
    nominal quality different?

     
     
     
     
     

    Summary

    Part 2:
     

    Data collection methods


    More on measurement


     


    hypotheses are predictions about the value of a particular variable or relationships between variables
     
     

    independent variable = explanatory variable
     

    dependent variable = response/outcome variable
     
     
     

    Research design

    Miscellaneous terms


    Summary