Possible Relationship Between Variables

When the null hypothesis has been rejected for a specific alpha value, any of the following five possibilities can exist.

1. There is a direct cause-and-effect relationship between the variables. That is, x causes y. For example, water causes plants to grow, poison causes death, and heat causes ice to melt.
2. There is a reverse cause-and-effect relationship between the variables. That is, y causes x. For example, suppose a researcher believes excessive coffee consumption causes nervousness, but the researcher fails tom consider that the reverse situation may occur. That is, it may be that an extremely nervous person craves coffee to calm his/her nerves.
3. The relationship between the variables may be caused by a third variable. For example, if a statistician correlated the number of deaths due to drowning and the and the number of cans of soft drink consumed during summer, he/she would probably find a significant relationship. However, the soft drink is not necessarily responsible for the deaths, since both variables may be related to heat and humidity.
4. There may be a complexity of interrelationships among variables. For example. a researcher may find a significant relationship between students' high school grades and college grades. But there probably are many other variables involved, such as IQ, hours of study, influence of parents, motivation, age, and is instructors.
5. The relationship may be coincidental. For example, a researcher may be able to find a significant relationship between the increase in the number of people who are exercising and the increase in the number of people who are committing crimes. But common sense dictates that any relationship between these two values must be due to coincidence.

By: Patrick Anthony M. Alcantara