I have a study where I did a sample size calculation using N=2800, CI=95%, margin or error = 3.5% to yield n=613.
In the study (auditing of charts), I wanted to look at the error rate in my sample. I came up with 41 errors so p=41/613=0.067
I want to know if this proportion is significantly higher than what I should expect so I thought I could use the test of single proportion, however, to calculate this, I need both my sample proportion (p) and my population proportion (pi).
My question is --> how do I know my population proportion? Is it the same as the margin of error? Maybe I'm using the wrong formula even?