Sample size calculation

[emma19901]

Hi, I have a dataset I am working with., I have one variable of interest were the subjects answer, Yes or no " in this case the subject could only answer exposure to radon' based on their perception only once.   I have the proportions of yes and the proportion of no's. I want to know how many no's can I include for further analysis. Should I use Proc Power one sample means or two sample means?

Thanks for your help in advance

[Reeza]

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@emma19901 wrote:

Hi, I have a dataset I am working with., I have one variable of interest were the subjects answer, Yes or no " in this case the subject could only answer exposure to radon' based on their perception only once.   I have the proportions of yes and the proportion of no's. I want to know how many no's can I include for further analysis. Should I use Proc Power one sample means or two sample means?

Thanks for your help in advance

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.That’s not how power analysis works. You do not calcualte power after an experiment, you use the data you have. 

http://daniellakens.blogspot.com/2014/12/observed-power-and-what-to-do-if-your.html?m=1

If you’re doing this before your experiment, I would use ONESAMPLEFREQ.

[emma19901]

With their answers, I will create a new variable called the likelihood of true exposure using a Likert scale. I need a sample size for two major reasons a) I can not use only all the yes responses (I need to include also no) not doing so will be biased, B) is a large dataset and I want to compare later probably by using a Wilcoxon my interpretation of the likelihood with 3 more people that will do the same process. For time reasons they can only analyze a fraction of the dataset. 97/1,500 answered yes 1403/1500 said no

[VDD]

the chance that anyone of the 3 being added to your sample with a reply of yes is 0.

1/15 would possibly answer yes.