A study of five hundred adults found that the number of hours they spend on social networking sites each week is normally distributed with a mean of 14 hours. The population standard deviation is 3 hours. What is the margin of error for a 95% confidence interval?

Margin of error formula:

ME = z * (Sigma) / √ n

z = 1.96 for a 95 % confidence interval;

Sigma = 3 (the population standard deviation)

n = 500

ME = 1.96 * 3 / √500 =

= 1.96 * 3 / 22.36 =

= 5.88 / 22.36 = 0.263

Answer:

The margin error for a 95% confidence interval is 0.263.