Click on the links below and take cornel summarization notes.
The Variables:
1. http://www.cool-science-projects.com/independent-and-dependentvariables.html
2. http://www.sciencebuddies.org/science-fairprojects/project_variables.shtml
3. http://www.lhup.edu/sboland/independent_and_dependent_variab.htm
4. http://www.fair.science-resources.org/sci_meth.htm
Purpose of Controls:
A control is an experiment or test where you already know the results. It is used as a standard of comparison to the experiment that you want to
do. If your control does not give the expected results or an outlier of results, this is an indication that there is something wrong with the
constant conditions in your experiment. A control is a part of the experiment that tests whether the system
behaves as it should. Controls serve two somewhat related purposes in an experiment. The first is that they show that the system is behaving as one expects from previous
knowledge, experience, and observation. This is necessary to allow an interpretation of the experiments.
The second, which is equally useful, is that, if (or better, when) something goes wrong, it makes it possible to pinpoint the error in
the experiment so that it can be corrected for the next time it is done.
Source: http://www.biochem.arizona.edu/classes/bioc568/Controls.htm2
Research Design methods:
1. http://www.socialresearchmethods.net/kb/design.php
Validity:
1. http://writing.colostate.edu/guides/research/relval/pop2b.cfm
2. http://www.socialresearchmethods.net/kb/desexper.php
An experiment is internally valid to the extent that it shows a cause-effect relationship between the independent and dependent variables.
Source:
http://psych.athabascau.ca/html/Validity/concept.shtml
So controls or constant variables help to maintain validity
Experimental Design
- A blueprint of the procedure that enables the researcher to test his hypothesis by reaching valid conclusions about
relationships between independent and dependent variables. It refers to the conceptual framework within which the experiment is
conducted.Source: http://www.okstate.edu/ag/agedcm4h/academic/aged5980a/5980/newpage2.htm