Just a single tricky question, for learning purpose, I'd appreciate who can tell me what to change to make it correct:
Which of the followings is true?
a) If a research draws 10000 random samples, each of a sample size 1000, he expects about 500 of his sample would not include the population mean
b) Confidence intervals can be derived for both population means and population proportions
c) Confidence intervals can be derived for both sample means and sample proportions