Answer
a. 2006-2007, 18
b. 2010-2011, 3
c. 2010-2011, 20
d. 1997-1998, 7
e. 2009-2010
f. 6
g. No, the graph shows that the sum of the number of strikes with the average number of days remain roughly unchanged. This means that when you restrict the number of strikes, the average number of days will increase as indicated by the data at year 2010-2011.
Work Step by Step
see above.