What is a real-world example of a t-test

Answer 1

Basically, it's anything you might test to determine if a theorized value is correct. For instance, in polling data, you might select a number of voters and determine whether they support a particular candidate (p>.5) or not (p<=.5). Or if a test concluded that 7 of 30 people had a genetic defect, then you could pick a sample of 30 and see how many had that genetic defect and then determine if the likelihood of that happening is high (p-value > .05) or low (p-value < .05). Just note that any t-test will look very much like a z-test, just without a known population standard deviation and/or a small sample size (30 is generally a good cutoff, but you're perfectly fine using a t-test for sample sizes above that; it eventually becomes a normal distribution anyways). Did that answer your question?