Here is a sample stat problem. I need to find E, the forumula for E is E = Zc * sqrt(p)(q)/n. For the question n = 900 p = .63 q = .37. And zc = 2.575. This plugged into forumula is E = 2.575 *sqrt(.63)(.37)/900. The answer, according to the book should be 0.041. What my issue is that when I put this in my calculator (ti-82) I get a totally different answer, that being 0.013. There are more decimal places but I dont feel the need to add them all. As you can see I am getting a completly different answer. I doubt the book is wrong but I don't know what the heck I am doing incorrectly, I tried plugging this into my calculator in many different ways and get the same result everytime. So someone please tell me what the heck is going on? I tried using a Ti-83 emu to see if I would get a different result, nope same answer.