Unoccupied Seats on Flights Cause Airlines to Lose Revenue $[ 4.86 \quad 18.34 ]$

Unoccupied seats on flights cause airlines to lose revenue.Suppose a large airline wants to estimate its average number of unoccupied seats per flight over the past year.225 flight records are randomly selected and the number of unoccupied seats is noted,with a sample mean of 11.6 seats and a standard deviation of 4.1 seats.Calculate a 90 percent confidence interval for ?,the mean number of unoccupied seats per flight during the past year.

A) $[ 4.86 \quad 18.34 ]$
B) $[ 11.25 \quad 11.95 ]$
C) $[ 11.57 \quad 11.63 ]$
D) $[ 11.15 \quad 12.05 ]$
E) $[ 11.30 \quad 12.20 ]$