1.5 Observational vs. Experimental

1.5 Stats

2. Objective: To explain the difference between and
observational and an experimental study.
1-5: Observational and Experimental Studies

3. 1) Observational Study: A study in which the
researcher merely observes what is happening or what
has happened in the past and tries to draw conclusion
based on these observations.
2) Experimental Study: A study in which the
researcher manipulates one of the variables and tries
to determine how the manipulation influences other
variables.
1-5: Observational and Experimental Studies

4. Quasi-experimental study: A study in which random
assignment is not possible so researchers use intact
groups. Often used in education (intact groups are
existing classrooms).
1-5: Observational and Experimental Studies

5. Independent Variable: The variable in an
independent study that is being manipulated by the
research. Also called the Explanatory Variable.
Dependent Variable: The resultant variable. Also
called the Outcome Variable.
1-5: Observational and Experimental Studies

6. Treatment Group: The group in an experimental
study that received the special instruction.
Control Group: The group that did not receive the
special instruction.
1-5: Observational and Experimental Studies

7. Advantages:
Experimental: 1) researcher can decide how to select
subjects and how to assign them to different groups 2)
researcher can manipulate the independent variable
1-5: Observational and Experimental Studies

8. Disadvantages:
Experimental:
1) May occur in unnatural settings (labs, classrooms)
2) Hawthorne Effect: subjects change their behavior
when they know they are participating in a survey.
3) Confounding Variables: A variable that influences
the dependent or outcome variable but cannot be
separated from the independent variable (exercise
program to study affect on health-subjects also change
diet, but researcher doesn’t know – diet has affect on
health, too).
1-5: Observational and Experimental Studies

9. Assignment: p. 16, Applying the Concepts, # 1-6
1-5: Observational and Experimental Studies

10. Assignment: p. 16, Applying the Concepts, # 1-6
1-5: Observational and Experimental Studies