q33 hw thank you

i) A study at the Veterans Administration Medical Center sought to assess whether their method of gradual desensitization therapy was successful in reducing the effects of post-traumatic stress disorder. Eighty veterans were assessed using a customized ratio scale that measures the severity of PTSD symptoms and then given eight weeks of desensitization therapy, after which they all were assessed again. What is the most appropriate statistical test to use to determine whether the therapy had an effect