SQRT error

Dear all, 

I need some help. 

I am trying to calculate the margin of error for a set of surveys. 

My formula is as follows:

1.96*sqrt( ( p*(1-p)/n ) * ( (N-n)/(N-1) ) )

I cannot get the SQRT function to work in dax so I have split my work up to a series of steps to aid analysis. My data now looks like this. my measures are in bold and I have included the calculation for each one. 

I now cannot get the final step of the equation to work. 

MOE = SQRT(FullDataset[MOE a]) but this does not work. I get an error. Can I get a square root of a measure? Or could it be due to a few infinity results in MOE a? There is also a NaN result. Woudl this make a difference?

It seemed like this was going to be so straightforward but I am very new to this and I just cannot figure this out. 

Any help would be appreciated