In 2011 the U.S. Department of Transportation reported with 95% confidence that the average length of a motor vehicle trip in the United States was 9.72 miles with a margin or error of 0.22 miles.

Question

In 2011 the U.S. Department of Transportation reported with 95% confidence that the average length of a motor vehicle trip in the United States was 9.72 miles with a margin or error of 0.22 miles.

With 95% confidence the authors of the report are claiming that the true average length of a motor vehicle trip in the United States is between __ and  __ miles.

The level of confidence for this estimate is___ %.

Answer 1

This would be 9.72-0.22 or 9.50 miles lower limit

and 9.72+0.22 or 9.94 miles upper limit.

This is a 95% CI as stated.