A null hypothesis is a hypothesis that proposes no relationship or difference between two variables. "In the standard hypothesis-testing approach to science one attempts to demonstrate the falsity of the null hypothesis, leaving one with the implication that the alternative, mutually exclusive, hypothesis is the acceptable one." (Reber, 1985, p. 337)
A null hypothesis is "the hypothesis that there is no relationship between two or more variables, symbolized as H0" (Rosenthal & Rosnow, 1991, p. 624).
The alternate, or research, hypothesis proposes a relationship between two or more variables, symbolized as H1.
If a researcher was interested in examining the relationship between music and emotion, s/he may believe that there is a relationship between music and emotion. However, a more specific, testable proposition is needed for research purposes. After a review of the literature, the researcher forms a research hypothesis, as well as a null hypothesis.
H1 (the research/alternate hypothesis): Music at a fast tempo is rated by participants as being happier than music at a slow tempo.
H0 (the null hypothesis): Music at a fast tempo and at a slow tempo is rated the same in happiness by participants.
"Note that the two hypotheses we propose to test must be mutually exclusive; i.e., when one is true the other must be false. And we see that they must be exhaustive; they must include all possible occurrences." (Rosenthal & Rosnow, 1991, p. 39)
Next, a researcher must translate the research hypothesis into operational terms. The researcher goes on to operationally define fast tempo as being music at a tempo of 120 bpm (beats per minute) and slow tempo music as being music at a tempo of 60 bpm. In addition, a researcher has to specify how participants are going to rate the music for happiness.
Reber, A. S. (1985). Dictionary of psychology. New York: Penguin Books.
Rosenthal, R., & Rosnow, R. L. (1991). Essentials of behavioral research:
Methods and data analysis (2nd ed.). New York: McGraw-Hill, Inc.