STAT 200 Chapter Notes - Chapter 3: Randomized Experiment, Homesickness, Dependent And Independent Variables
Document Summary
We are often interested in the relationship between two variables. Two variables are associated if values of one variable tend to be related to values of the other. Two variable are causally associated if changing the value of one variable influences the value of the other variable. When "no link is found" - there is neither association nor causation. Infection from the zika virus causes birth defects such as microcephaly. Cat owners tend to be more educated than dog owners. Your grades will fall if you party frequently. A third variable that is associated with both the explanatory variable and the response variable is called a confounding variable. The effect of a confounding variable on the response cannot be separated from the effect of the explanatory variable. You might also hear confounding factor or lurking variable. When confounding variables are present, a causal association cannot be determined.
