In the August 12 2007 issue of Parade magazine which comes w

In the August 12, 2007, issue of Parade magazine (which comes with the Sunday newspaper for millions of Americans), readers were asked to go online and vote on this question: Should the drinking age be lowered? The results were published in the October 7 issue; more than 14,000 readers voted, and 48% said

Solution

p= 0.48
n = 14000
z_c= 2.58 at 99% confidence.

margin of error, E = sqrt(pq/n)*z_c
= sqrt(0.48*(1-0.48)/14000)*2.58
= 0.011

99% CI = (p - E, p + E)
= (0.48 - 0.011, 0.48 + 0.011)
= (0.469, 0.491) (Ans.)