SCENARIO: A researcher believes exercise may affect anxiety in women, but research appears inconclusive. She identifies a group of women (N = 30) who have not exercised before but are planning to begin exercising. She gives them a 50-item anxiety inventory before they begin exercising and administers it again after six months. The anxiety inventory is measured on an interval scale; higher numbers indicate Historyhigher anxiety. In addition, scores on the inventory are typically distributed. The mean of the difference scores is 3.4, S_D = 1.8, and there were 30 in the sample. Using this information, answer the following questions showing all work when calculations are required to earn up to full credit.

4)Calculate the correlated-groups t-test to determine the t_op. (Note that you will first have to solve for the standard error of the difference score).