Help with statistics question

Posted on 2014-04-01 06:21:00 in Statistics by CHELS

I cannot figure this problem out. I have used the formula that our teacher gave us and rounded to the nearest whole number but I just don't know what I did wrong. I need help to see what I am doing wrong! Thank you!



How large a sample should be taken if the population mean is to be estimated with 90% confidence to within $69? The population has a standard deviation of $892. (Round you answer up to the nearest whole number.)



Formula given to us: [(z-scoreXstandard deviation)/max. error of estimate]squared

What I did: [(1.65x892)/69]squared then rounded to the nearest whole number and I got 455.



Apparently this is wrong and I don't know why!

---

Answer Comment

No Answers Posted Yet.