111 Unoccupied seats on flights cause airlines to lose revenue Suppose a large airline wants to estimate its mean 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 6 seats and the sample standard deviation is 4 1 seats a 1 x ii Sx iii n iv n 1 b Define the random variables X and X in words c Which distribution should you use for this problem Explain your choice d Construct a 92 percent confidence interval for the population mean number of unoccupied seats per flight i State the confidence interval ii Sketch the graph iii Calculate the error bound 112 In a recent sample of 84 used car sales costs the sample mean was 6 425 with a standard deviation of dintribution is approximately normal