A certain survey conducted had a population proportion of at most 22% for people who agreed. What is the confidence level if 20% of the people sampled agreed, and the standard error of the proportion is ±1%?

Question

amistre64 · Answer

the standard error is defined as  $$\sigma/\sqrt n$$
which is part of the confidence interval calculations if memory serves.

amistre64 · Answer

given:$$z=\frac{\hat p-p}{\sigma/\sqrt n}$$
the CI is simply:$$\hat p\pm z(\sigma/\sqrt n)$$

amistre64 · Answer

the z is determined by the level of significance.  usually as 90, 95, or 99%