Re: sampling error (e15q20)
100% confidence level is never used. There is no 100% confidence level because we can never say we are 100% confident.
I would assume 95%. That is mostly the case. Therefore, z=1.96
If we use a 95% C.I., then the margin of error is .049
We subtract from and add to the percentage, which is 56%
.56-.049=.511
.56+.049=.609
Confidence Interval: \(\displaystyle 0.511\leq p\leq 0.609\)