I've been trying to formulate this question and have struggled, so if it seems ill-worded, I apologize:
A statistics book I have has a table in the back that says:
- For an inference test regarding a proportion, generally a z-test is used.
- For an inference test regarding a mean, a t-test is generally used.
- For an inference test regarding “goodness of fit”, a chi-square test is generally used.
- For an inference test regarding association between two quantitative variables, a t-test is used.
How are these decisions made? How can I know that a “goodness of fit” test statistic is optimally calculated by a chi-square statistic, etc.
Additionally, how is it that the normal distribution somehow fits the proportion (z) statistic, but not a t-distribution, or chi-square distribution, etc.?