Sample Size Calculator (one group versus population)

#1
Dear all,

so far I couldn´t find a solution to calculate the required sample size for the following scenario:

Goal: Research continuous variables (cost perceptions) of a population through one sample group. --> means of one group need to be significant for the entire population.

Population: 7.500.000
Confidence Level: 95%
Confidence Interval: 3

Are there any information missing like power level and does anyone know how I can calculate the required sample size for this scenario? Especially through an online tool would be highly appreciated.

Thanks very much.

Chris
 
#2
It sounds like you are asking for the sample size needed to get a 95% confidence interval for a population mean (calculated from from one sample) to be +/- 1.5 but it isn't clear to me. If so the missing information is the SD of the data.
Can you explain a little more please? kat