Basic Experimental Design

 A researcher examined the effect of relaxation training on insomnia.  Subjects received 0, 2, 4, or 8 sessions of relaxation training.  Following training, the researcher measured how long it took the participants to fall asleep in their homes.  The average time for each group is presented in the following table:  

TRAINING SESSIONS                      MEAN TIME (minutes)

                 0                                                  72

2                                                  58

4                                                  31

                 8                                                  14                   

1.           Provide definitions for independent variable and dependent variable.

 

 

2.           Identify the independent and dependent variables in the above scenario.

 

3.           How many levels of the independent variable are there?  Explain.

 

4.           Is the independent variable quantitative or qualitative?  Explain.


 

5.           Given the specifics of the experiment presented above, discuss a possible confounding variable.