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. to accomplish this, the records of 225 flights are randomly selected and the number of unoccupied seats is noted for each of the sampled flights. the sample mean is 11.2 seats and the sample standard deviation is 4.3 seats. note: if you are using a student's t-distribution, you may assume that the underlying population is normally distributed. (in general, you must first prove that assumption, though.)