The shape of the distribution of the time required to get an oil change at a 15-minute oil-change facility is unknown. however, records indicate that the mean time is 16.2 minutes, and the standard deviation is 3.4 minutes. suppose the manager agrees to pay each employee a $50 bonus if they meet a certain goal. on a typical saturday, the oil-change facility will perform 40 oil changes between 10 a. m. and 12 p. m. treating this as a random sample, at what mean oil-change time would there be a 10% chance of being at or below? this will be the goal established by the manager.

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?