To find which measure of variability is greater and which average number of monthly fatalities is higher, you will need to calculate the mean and the mean absolute deviation for both years
The mean will tell us which is generally higher, and the mean absolute deviation will tell us which has a greater variability.
It is just the multiplication of vectors. We'll multiply corresponding pairs together. The general formula for the pairs of (; ) and (; ) is * + * = (-6)*(-3)+4*6=18+24=42