A survey of 3000 British residents found that only 21 percen

A survey of 3,000 British residents found that only 21 percent wished to see the monarchy abolished. If the survey was random, compute the following for the percentage wishing to see the monarchy abolished.

a) the 95% margin of error: ________________________________________

b) the 95% confidence interval: __________________________________________________

Solution

margin of error will be : srqt ( 0.21 * (1-0.21) / 3000 )

srqt ( 0.0000553 )

margin of error = 0.0074

95% confidence interval

alpha = 0.05

alpha / 2 = 0.025

Z= 1.96

I: 0.21 +/- 1.96 * 0.0074

0.21 +/- 0.014504

0.195496 < p < 0.224504