1) Why might the t-test be more useful in actual practice rather than a z-test?

https://www.youtube.com/watch?v=quZAwDmcEbE After watching this video answer the following:

What is the significance and the confidence intervals telling you about the two classes with regard to their scores on the quiz?

If one of these classes was a class you taught and your principle asked you to interpret this data what might you say?

3) Explain a detailed answer as to why we might run an ANOVA over a t-test and what factors are in consideration in choosing an ANOVA instead of a t-test.

4) Why do we run a post-hoc test when after having calculated an ANOVA that found statistically significant results?

What is the significance of a post-hoc test containing zero within the confidence intervals?