Author 
Topic 

SamanthaX
New Member
USA
1 Posts 
Posted  10/15/2007 : 18:23:49

With a confidence level of .95 and a confident interval of 5 and a population of 20,000 what is the sample size?
With a confidence level of .99 and a confident interval of 5 and a population of 20,000 what is the sample size?
Finally, using the sample size for question 1 and 2 and a response distribution of 50% (i.e., percentage box) what is the confidence interval for questions 1 and 2.
If you had the time to explain how you figured those out, that would help me tremendously :~) Thank you in advance for any assistance you can provide Sincerely, Grateful



tkhunny
Advanced Member
USA
1001 Posts 
Posted  10/16/2007 : 12:29:43

Didn't we do this one already?
You should have a formula, something like this:
n = zs/d
n is the sample size z is the zscore associated with your confidence level s is your variance, calculated, estimated or assumed. It is accepted practice to use a nice upper bound, failign other information. d is the maximum acceptable deviation.
I'm not sure your questions have sufficietn information, but give it some thought. 



Topic 


