Question

in a study of crime, the FBI found that 13.2% of all Americans had been victims of crime during a 1-year period. This result was based on a sample of 1,105. Estimate the percentage of U.S. adults who were victims at the 90% confidence level. What is the lower bound of the confidence interval?

Please round to the nearest whole number.

I put 11 and I got it wrong

Answer 1

Solution :

Point estimate = sample proportion = = 0.132

Z = 1.28

Margin of error = E = Z* (( * (1 - )) / n)

= 1.28 * (((0.132 * (1 - 0.132)) / 1105)

= 0.013

Lower bound = 0.132 - 0.013 = 0.119 = 11.9% = 12%

12