Examples of Spurious Relationships
| Observed Spurious Relationship | Reason for the Relationship (the Third Variable) |
| Amount of ice cream sold and deaths by drownings (Moore, 1993) | Season: Ice cream sales and drownings tend to be high during the warm months of the year. |
| Size of left hand and size of right hand | Genetics: The size of both hands is due to genetic makeup. |
| Height of sons and height of daughters (Davis, 1985) | Genetics: Heights of sons and daughters are both due their parents’ genetic makeup. |
| Ministers’ salaries and price of vodka | Area (i.e., urban or rural): In urban areas, prices and salaries tend to be higher. |
| Shoe size and reading performance for elementary school children | Age: Older children have larger shoe sizes and read better. |
| Number of doctors in region and number of people dying from disease | Population density: In highly dense areas, there are more doctors and more people die. |
| Number of police officers and number of crimes (Glass & Hopkins, 1996) | Population density: In highly dense areas, there are more police officers and more crimes. |
| Number of homicides and number of churches | Population density: In highly dense areas, there are more homicides and more churches. |
| Number of storks sighted and the population of Oldenburg, Germany, over a six-year period (Box, Hunter & Hunter, 1978) | Time: Both variables were increasing over time. |
| Number of public libraries and the amount of drug use | Time: Both were increasing during the 1970s. |
| Teachers’ salaries and the price of liquor (Moore and McCabe, 1993) | Time: Both tend to increase over time. |
| Tea drinking and lung cancer | Smoking: Tea drinkers have a lower risk only because they smoke less. |
Table 11.2: Examples of Spurious Relationships
http://www.southalabama.edu/coe/bset/johnson/oh_master/Ch11/Tab11-02.pdf
OVERHEAD MASTERS
http://www.southalabama.edu/coe/bset/johnson/2oh_masters.htm
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Educational Research
Quantitative, Qualitative, and Mixed Approaches
by R. Burke Johnson and Larry Christensen
PART 4 SELECTING A RESEARCH METHOD
Chapter 11: Nonexperimental Quantitative Research
http://www.southalabama.edu/coe/bset/johnson/lectures/lec11.htm