Sorting: 8, 14, 18, 23, 26, 27, 29, 3 1.

Median =23 or 26

(2)23 is the median and close to the average of 22, so it is more appropriate to use the flight time of G as the representative.

(3) Average value = (18+14+26+29+27+23+31)/7 = 24.

Using 24 to represent the experimental level is close to the median of 23, but it exceeds the average of 22, which is not in line with the basic situation.