Hypothesis
is a specific statement of prediction. It describes in concrete (rather than theoretical)terms what you expect to happen in your study.
Alternative Hypothesis
A specific statement of prediction that usually states what you expect will happen in your study.
Null hypothesis
The hypothesis that describes the possible outcomes other than the alternative hypothesis. Usually, the null hypothesis predicts there will be no effect of aprogram or treatment you are studying.

One-tailed hypothesis
A hypothesis that specifies a direction; for example, when hyour hypothesis predicts that your progra will increase the outcome. pg. 8
Two-tailed hypothesis
A hypothesis that does not specify a direction. For example, if your hypothesis is that your program or intervention will have an effect on an outcome, but you are unwilling to specify whether that effect will be positive or negative, you are using a two-tailed hypothesis.