Generalizability of survey results example
About this video
Estella's department surveys a large simple random sample of first-year students living in the 12 residence halls she oversees. The video explains that the results can be safely generalized only to all first-year students in those 12 halls, not to other halls or to students beyond their first year.
You'll be able to
- decide which population a random sample's results can be generalized to.
- explain why results can't be generalized to groups that weren't sampled from.
Key words
- simple random sample
- A sample where every member of the group being sampled has an equal chance of being chosen.
- generalize
- To use results from a sample to make statements about a larger population.
Transcript
- [Instructor] First-year students at a certain large university are required to live on campus in one of the 24 available residence halls. After their first year, students have the option to live away from campus, but many choose to continue living in the residence halls.
Estella oversees 12 of these residence halls. Her department surveyed a large simple random sample of first-year students who live in those 12 residence halls about their overall satisfaction with campus living. Estella can safely generalize the results of the survey to which population?
So pause this video, and see if you could figure it out. All right, so let's do this together. So Estella has done, it's a large simple random sample of first-year students. So let's see, choice A is only those students who were surveyed. Well, no, this was a simple random sample, and it was a large sample, so it's meant to be indicative of all first-year students.
You can generalize more than just making statements about just the students who were surveyed. All first-year students, but only those who live in these 12 residence halls. Yeah, I think this one looks fair because you can't generalize to people who don't live in those residence halls.
Maybe Estella oversees the 12 best residence halls or the 12 worst residence halls, and so you wouldn't get, if that were the case, you would not be able to generalize beyond that. Or these might be the 12 that are closest to campus or the 12 that are furthest from campus.
So you can only generalize to people who live in those residence halls. All students, first-year and not, but only those who live in these 12 residence halls. Well, the issue here is, is that a second-year student or a third-year student might just have a different perspective, even if they live in those, in that same building and we did a large random sample of first-year students.
We didn't do a large random sample of all people in that, in that, those 12 residence halls, so rule that out. All first-year students at the entire university, but not students beyond their first year. Well, this wouldn't make sense because there would be first-year students who would be outside of those residence halls.
And as I already mentioned, the ones that Estella manages might not be indicative of where all of the first-year students in this university live.
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