(I just need to edit my homework, my teacher asked to make our answers short without explanation!)

1- A researcher examines whether student's choice of enrolling in a summer Math class is influenced by students reading an article on the growth mindset. Half the students read the article and half did not.

A. The independent variable is students reading an article on the growth mindset.
B. The independent variable is a categorical independent variable as it involves two categories.
C. The dependent variable in this research is
"students' choice of enrolling in the summer
Math class."
D. There are two levels for the independent variable.
E. The scale of measurement for the dependent variable is nominal.

2- A researcher examines whether scores on a Statistics final exam (0 points to 100 points) are influenced by whether background music is soft, loud, or absent. (Note: Assume the students have been successfully completing quizzes up to the final exam.)
A. The independent variable in this study is the background music (soft, loud, or absent).
B. The independent variable is categorical.
C. The dependent variable in this study is the scores on the Statistics final exam.
D. There are three levels for the independent variable.
E. The scale of measurement for the dependent variable is an interval scale.

3- A researcher compares freshmen, sophomores, juniors, and seniors with respect to how much fun they have while attending college (scale: 0=no fun at all, 1, 2, 3, 4, 5, 6 to 7=maximum amount of fun). (Note: Assume equal intervals in the scale and a true zero point.)
A. The independent variable is the students: freshmen, sophomores, juniors, and seniors.
B. The independent variable is categorical.
C. The dependent variable in this study is the level of fun experienced by the students while attending college.
D. There are four levels for the independent variable: freshmen, sophomores, juniors, and seniors.
E. The scale of measurement for the dependent variable is nominal.

4- A researcher examines whether taking Vitamin D supplements (0x a day, 1x a day) influences self-reported depression (measured as either “depressed” or “not depressed”).
A. The independent variable is the frequency of taking Vitamin D supplements.
B. The independent variable is categorical.
C. The dependent variable is self-reported depression (measured as either "depressed" or "not depressed").
D. There are two levels for the independent variable: Ox a day and 1x a day.
E. The scale of measurement for the dependent variable is nominal.

BONUS A researcher examines whether being in a room with blue walls, green walls, red walls, or beige walls influences aggressive behavior in a group of adolescents. The adolescents are given simulated, electronic games where they are required to administer shocks. The researcher will then rank the results of the room where the most shocks occurred (1st, 2nd, 3rd, and 4th).
A. The independent variable is the color of the room walls.
B. The independent variable is categorical.
C. The dependent variable is the number of shocks administered.
D. There are four levels for the independent variable.
E. The scale of measurement for the dependent variable is nominal.