The prediction that alcohol slows reaction time is

This question is in the context of research. The answer is directional or one-tailed hypothesis. This is because the researchers have specific hypothesis that predicts the direction of the experimental effect (i.e. the researcher expects that alcohol consumption slows reaction time). The researcher will then formulate a null hypothesis (H0) that suggests that alcohol does not slow reaction time and another alternative hypothesis (HA) that suggests that alcohol slows reaction time. 

Dont understand the question