Karen is a college student who has experienced moderate feelings of sadness and worthlessness for over 2 years. Most of the time, she still goes to class and meets her other obligations. Occasionally, however, her depressive symptoms intensify. When this occurs, she stops going to class, isolates herself, and even experiences suicidal thoughts. Karen could be diagnosed with:

Dr. redbull conducts a study to determine whether her new energy drink children perform better on spelling tests. she randomly assigns children to one of two groups: group 1 receives her energy drink and group 2 receives water. she then gives both groups a spelling test and compares the results. which of the following is true about this study? a. group 1 is the dependent variable and group 2 is the independent variable. b. this is a correlational study. c. group 2 is the experimental group. d. the independent variable is the type of drink the children receive.