Desta wants to purchase "The Ultimate Plan" from her cell phone provider. If she enrolls in this plan, she can purchase the latest cell phone from the provider for $250. The plan
consists of unlimited talk and text and 18GB of data for $100 per month. It will cost an
extra $20 per month to add her husband's phone to the plan and an extra $10 per
month to have her tablet connected.
a. Set up Desta's monthly cost function for this plan. Let x represent the number of
months she has been on the plan,
b. What will be her average cost per month be after being on the plan for 3 months?
c. Approximately how many months does Desta have to be in the plan for her average
monthly cost to be $140?

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?