Testing of Hypothesis
The researcher is similar to the prosecuting attorney is the sense that the researcher brings the null hypothesis “to trial” when she believes there is probability strong evidence against the null.
- Just as the prosecutor usually believes that the person on trial is not innocent, the researcher usually believes that the null hypothesis is not true.
- In the court system the jury must assume (by law) that the person is innocent until the evidence clearly calls this assumption into question; analogously, in hypothesis testing the researcher must assume (in order to use hypothesis testing) that the null hypothesis is true until the evidence calls this assumption into question.
and 
) are equal; the alternative hypothesis says that they are not equal.
) is zero; the alternative hypothesis says that it is not equal to zero.
) is zero, and the alternative says that it is not equal to zero.