When sandra was 18 years old, she was in a serious car accident. although she made a full recovery from her injuries, she experienced extreme anxiety afterward. sandra is now very anxious when driving, will not drive near the site of the accident, has nightmares about the accident, and flinches when she goes through intersections. sandra has symptoms suggestive of

a. generalized anxfety disorder.
b. a specific phobia.
c. panic disorder frequently accompany obsessions and appear to serve the function of reducing
d. post-traumatic stress disorder.

The authors of the paper "fudging the numbers: distributing chocolate influences student evaluations of an undergraduate course"† carried out a study to see if events unrelated to an undergraduate course could affect student evaluations. students enrolled in statistics courses taught by the same instructor participated in the study. all students attended the same lectures and one of six discussion sections that met once a week. at the end of the course, the researchers chose three of the discussion sections to be the "chocolate group." students in these three sections were offered chocolate prior to having them fill out course evaluations. students in the other three sections were not offered chocolate. the researchers concluded that "overall, students offered chocolate gave more positive evaluations than students not offered chocolate." indicate whether the study is an observational study or an experiment. give a brief explanation for your choice.