In this example, on step three it tells me to evaluate the function for two values of x, which they use -2 and -1 as you can see under step three. However, I am unable to figure out where they got those x values from and where I should get my x values from when I have to answer a question like this. Where did they get their x values from and how do I get my x values in a problem like this?

Stu and ambrose are working together on a study of whether diet is related to students' mental health. first, they randomly select 10 students from the student center and 10 students from the office of counseling and psychological services. then, they ask students to rate their diet in terms of healthiness on a scale of 1-100 before completing a 20-item mental health survey. a) name one of the constructs being studied b) how was the construct you named above operationally defined in this experiment? e) was the variable you described above their independent variable, their dependent variable, or a controlled variable? d) what is a confounding variable? what is a potential confound in this study?