In a recent poll 320 people were asked if they liked skiing

In a recent poll, 320 people were asked if they liked skiing, and 47% said they did. Find the margin of error of this poll, at the 95% confidence level.

As in the reading, in your calculations:
--Use z = 1.645 for a 90% confidence interval
--Use z = 2 for a 95% confidence interval
--Use z = 2.576 for a 99% confidence interval.


Give your answer rounded to three decimal places.

Solution

Total people = 320

P liked = 0.47

Q Not liked = 0.53

Sample size (N) = P ( 1-P ) (Zc / E)^2

320 = 0.47 * 0.53 ( 2 / E)^2

1284.625 = 4 / E^2

E = 0.0558