Eric wants to estimate the percentage of elementary school children who have a social media account. He surveys 450 elementary school children and finds 280 have a social media account. Identify the confidence interval at 99% confidence level. Find the confidence interval.

Z0.10 Z0.05 Z0.025 Z0.01 Z0.005

1.282 1.645 1.960 2.326 2.576

Use the table of common z-scores above.

Round 3 decimal places

p'=

std div p'=

za/2=

( , )