Answer:
a. An observational study
Step-by-step explanation:
An observational study is a study that has to do with the observation of individuals involved in the study. In such a study, zero effort is put to change the outcome.
This question tells us that the random sample of 291 individuals that underwent the weight loss program would go through a system of follow up to find out the change in weight. Therefore the design of the study is clearly an observational study.
Answer:

Step-by-step explanation:

I hope I helped you^_^
Answer:
Domain is: 0 ≤ n ≤ 75 where n is an integer
Step-by-step explanation: