Question 1201714
CI = p' ± z*(sqrt(p'*(1-p')/n))

First find the z-score.

Use calculator , we can find that the z-score for a 95% confidence interval which is approximately 1.96.

plug in the values:

CI = 0.88 ±{{{ 1.96*(sqrt(0.88*(1-0.88)/260))}}}


= 0.88 ± 0.057

Round to three decimals

CI = (0.823, 0.937)