Answer:
a person's mood has an effect on how helpful that person is likely to be
Explanation:
The hypothesis is the researchers opinion before the start of the experiment. The researchers opinion is that "a person's mood has an effect on how helpful that person is likely to be" this is the hypothesis before the start of the study. The null hypothesis in this study is most likely; a persons mood has no effect on how helpful that person is likely to be , i.e. effect of mood on the likelihood of an individual to help is zero while the alternative is that the effect of mood on the likelihood of an individual to help is not zero.