Students watched a cartoon and then rated how funny they thought the cartoon was. what are the independent, dependent, and controlled variables?

1) Students watched a cartoon either alone or with others and then rated how funny they found the cartoon to be. Investigative Question: Will the amount of friends watching a cartoon affect how funny it is? Independent Variable: The size of the group watching. (Think how are the groups made?) Dependent Variable: Number of laughs recorded per person or Rating scale of the cartoon afterwards. (Data) 2) A comprehension test was given to students after they had studied textbook material either in silence or with the television turned on. Investigative Question: Does the amount of noise affect how well you study? Independent Variable: How loud the study environment was. (Separated groups into with TV on or in silence) Dependent Variable: Score on the comprehension test. (Data) 3) Some elementary school teachers were told that a child’s parents were college graduates, and other teachers were told that the child’s parents had not finished high school; they then rated the child’s academic potential. Investigative Question: Does your parent’s academic achievements affect your academic potential? Independent Variable: Parent’s education level. (Groupings) Dependent Variable: IQ test, TN data, Core Class GPA, PSAT (Fair Data that every student can take) 4) Workers at a company were assigned to one of two conditions: One group completed a stress management training program; another group of workers did not participate in the training. The number of sick days taken by these workers was examined for the two subsequent months. Investigative Question: Will Stress Management Training (SMT) decrease the number of sick days taken? Independent Variable: Amount of SMT completed (Some went through the training and some did not) Dependent Variable: Number of sick days taken. 5) Students at a University were split into two groups and each received a different text for a philosophy course. Once group received a traditional text book, while the other received an interactive textbook on a tablet computer. After the course, the final exam marks between the two groups of students was compared. Investigative Question: Does technology increase test scores? Hypothesis: If a student uses an I-Book for the text, then there will be now increase in the final exam grade. Independent Variable: The type of text book Dependent Variable: Final Exam Scores Constant Variables: The test format, amount of time to take the test, prep materials given, pre-test routine, how the lessons are given, testing environment, relative age of students… 

Ithink the answer is d.