Vol. 3, No. 5
from Dr. Cleary
Will Ressque may have an opening with Mr. Drecters and his daughter if he learns this simple tool.
If two variables are related to each other in some way--as pH and time are in the example--a tool that can provide insight into the quality of the relationship is correlation analysis, or scattergrams. In cases where it can be determined that one factor has an effect on the other, this is known as regression analysis.
In regression analysis, the variable that is being predicted (pH levels, in
this case) is called Y (dependent variable), and the one that causes the changes
is known as the independent variable. (In this example, this would be time.) If Will were to use a scattergram to evaluate pH levels over time, it might
look like this:
To access a more complete discussion
of regression, including explanations of how to create scattergrams and when to
use them, go to http://www.pqsystems.com/eline/2001/05/tool_book.pdf.
Copyright 2001 PQ Systems.
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