Question

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?

Answer 1

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.