Need Data Collection help in an Experimental Design Discussion Forum for mt statistics class

Consider the following statistical studies. Which method of data collection would likely be used to collect data for each study? Explain your selection. What is the population of interest?

Would you take a census or use a sampling? Explain. If you would use a sampling, decide what type of sampling technique you would use. Explain your reasoning.

1. A study of the effect of exercise on relieving depression.

2. A study of the success of graduates of a large university in finding a job within one year of graduation.

3. A study of how often people wash their hands in public restrooms.