I am conducting a study for 1000 individuals. All of them answered no to the question. I have plugged the data in SPSS as 'no' for each individual. So 0% of my patients had yes. What can I say about the power or the generalizability of the study? I could not compute a 95% Confidence interval that shows that estimates the 'yes' in the general population (given that I had 0% of yes in my survey). Any help please?