- Thought Experiment: Sample 3 students at random and get their (sample) mean age. Do this
many, many, manyonly 3 times
- Question 1: Why do the sample means below vary?
- Answer 1: Because of the sampling variability induced by the random sampling!
- Question 2: What value quantifies how much these sample means vary by?
- Answer 2: The Standard Error!
|Random Sample||(Sample) Mean Age|
|Jack, Jared, Sam||21.7|
|Wengel, Rebecca, Steven||19.4|
|Stefan, Joccelyn, Sierra||20.0|
- PS-10 Discussion.
- Regular lecture during lab time tomorrow.
- Doodle Poll to fill 11 time slots to discuss projects, as a group.
Learning checks: Based on
- the example in the Lec27-B learning check discussion
- the chalk talk notes from Lec28
- Explicity compute the standard error when taking samples of size
- Discuss with your peers why they matter in any study that involves some kind of sampling.