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. 100 flight records are randomly selected and the number of unoccupied seats are presented in the file Empty_Seat1.xlsx. If 95% confidence interval for the population mean number of unoccupied seats is to be computed, what is the margin of error? and What is the sample size needed, if for a 95% confidence interval, the desired error rate is 1/2 seat?

Number of Unoccupied Seats Per day

9

8

13

9

0

12

11

11

9

15

7

15

12

11

15

3

17

9

6

9

15

20

9

13

6

12

16

11

14

13

12

11

15

16

11

7

7

13

16

8

14

9

10

0

6

7

22

2

13

16

11

10

12

4

11

10

18

11

9

12

7

13

7

15

7

-1

15

13

10

10

13

28

-4

16

3

13

10

10

1

8

4

11

21

4

13

15

17

16

10

19

8

9

13

15

7

11

7

7

11

9