Find the null and alternative hypotheses, Type I and Type II Error and determine whether the alternative hypothesis is directional or non-directional

Question

A researcher has developed a new therapy to treat anxiety, and wants to see how it compares to medication to treat anxiety. She randomly assigns participants to participate in therapy for 3 weeks or take the drug for 3 weeks and measures their anxiety levels after treatment. 

Answer 1

H0: There is not a significant difference in the treatment of anxiety between the new therapy and the medication. M = μ

H1: There is a significant difference between the new therapy and medication. M ≠ μ

Generally, the researcher is trying to reject the null hypothesis. Think about the null hypothesis as the status quo and the alternative as the change or innovation that challenges that status quo.

A Type 1 error would be rejecting of a true null hypothesis, while a type II error is the non-rejection of a false null hypothesis. Therefore, if there is not a significant effect of the new therapy and the researcher rejects H0, this is a type 1 error (saying there's an effect when there isn't one). If a researcher accepts H0, but H1 is actually true this is a type 2 error (saying there is no effect when there is one).

Nondirectional alternative hypothesis does not state the direction of the difference, it indicates only that a difference exists. In contrast, a directional alternative hypothesis specifies the direction of the tested relationship, stating that one variable is predicted to be larger or smaller than null value.