Obtaining a simple random sample is either not practical or inappropriate for these hypothetical research studies. Determine which alternative random sampling technique(s) would be appropriate to use for each study. In each case, choose techniques that are efficient and can be used on their own to acquire an unbiased population estimate. More than one technique may be appropriate for a study. Brianna wants to take a random sample of students at public four-year colleges in the United States to determine the mean number of social media posts students make per montlh It would be ???binlbr3???too expensive and time consuming for Brianna to obtain a list of all college students in the ???bin1br3???United States. She does not think the number of social media posts students make varies systematically ???binlbr3???among colleges Josh wants to obtain a random sample of students at his college to determine the proportion of students who have experienced clinical depression. He does not believe a simple random sample ???bi3br12???to be appropriate because he suspects that the proportion of students who have experienced clinical depression ???bin3br12???varies by gender Emily wants to obtain a random sample of students attending four-year colleges in the Boston metropolitan region to determine the average amount of time students spend at the library each semester. She cannot take a simple random sample because it would take too long for her to obtain ???bin2brl???a complete list of all students attending the 50 four-year colleges in the area. Also she suspects ???bin2br1???that the amount of time spent at the library will vary by major Answer Bank stratified sampling multistage sampling cluster sampling