Looking at a poll, 74% of California adults (374 out of 506 surveyed) believe that education is one of the top issues facing California. We want to construct a 90% confidence interval for the true...

Looking at a poll, 74% of California adults (374 out of 506 surveyed) believe that education is one of the top issues facing California. We want to construct a 90% confidence interval for the true proportion of California adults who believe that education is one of the top issues facing California.

How do I find the error bound? (note:I must round answer to three decimal places)