The directional hypothesis can be understood as a prediction that is made by a researcher in which he/she expects either a positive or a negative change in the relationship between two variables of any given population.
<u>These hypotheses can be made based on past experiments, the study of different research papers and empirical evidence.</u>
In this particular case, Jessica Hypothesizes that her manipulation of temperature in an auditorium will increase the number of students who doze off in a lecture. She is testing a Directional research hypothesis.