I am trying to find out a suitable population size for a survey that I want to develop.
I want alpha to be 0.95
The survey will have 40 questions, and each question with have 4 choices.
Thus, my question is, what is the size of the population that I should choose to make sure that I am 95% certain that I believe the results.
Also, so I can do this next time, can you explain the type of statistical test you used, and it's name? Thanks.
Answer In order to estimate the sample size you require some preliminary information mainly regarding the outcome of interest/dependent variable, whether you you are trying to estimate arithmetic mean or proportion(percentage). This information has to be based on some prior experience such as literature review /similar studies or pilot studie if no such information available.
So if you could state your objectives and some related information about main dependent variable, the sample size can be estimated.It seems you are conducting study based on 4 responses.I feel outcome/result can be expressed in terms of percentage, if you are using some scales it can be expressed as mean or median.
Regarding the statistical test for application, it is again based on object of comparison,study design and number of comaprative groups you are having , in relation to indepndent varaibles either parametric or nonparametric approach can be used.But at the moment I cant say which of the methods to be used for your study.If you could specificy your objectives and other methodolgical details, hypothesis etc, then it can be decided about sample size and statistical procedures.
