My professor said when sample size is large, it will has the following formula, but how big is the sample can be considered to be a large sample and use the following formula?
I did some questions in my book,and it seems like most of the question don't use the formula above. For example in a survey of 2003 American adults, 25% said they believed in astrology. a. Calculate and interpret a confidence interval at the 99% confidence level for the proportion of all adult Americans who believe in astrology.
I am really confused, I think 2003 is pretty big, so it can use the first formula....tomorrow is the final, and I still don't know which one to use... Really hope someone can answer my question, I will be really thankful