Below is a pair of hypotheses that are based on a correlation. They constitute a well -formed pair.

Research Hypothesis:
There will be a negative correlation between the amount of smoking per day and lung capacity such that the more cigarettes a person smokes a day the smaller is the person’s lung capacity during normal breathing.

Null Hypothesis:
There will be a positive correlation or no correlation between the amount of smoking per day and lung capacity such that the more cigarettes a person smokes a day the greater or the same is the person’s lung capacity during normal breathing.


Key Elements of Each Form of the Correlational Hypothesis:

The hypotheses shown above comprise a pair of well-formed correlational hypotheses because they clearly identify both variables in the relationship, i.e., rate of smoking per day and lung capacity during normal breathing, the expected relationship between the two variables, the set of expected relationships cover the full range of possible outcomes.

# of cigarettes smoked per day
--> variable #1

lung capacity during normal breathing
--> variable #2

will be a negative correlation
--> predicted direction of the relationship for the research hypothesis

will be a positive correlation or no correlation
--> predicted direction or absence of direction of the relationship for the null hypothesis