Solution:
1.
The average snowfall in cincinnati over this period was 28 inches.
In the city cincinnati, snowfall (inches) in january and february is 18 and 38 respectively :
Average snowfall = {18+38}/{2} = 28 inches
2.
If the march data on snowfall is above the average (i.e 28 inches), The monthly average will rise.
If the march data on snowfall is above the average snowfall in January and February (i.e 28 inches), the monthly average will rise because, any snowfall data in march which is greater than 28 inches will lead to rise in monthly average.
For e.g , suppose, If we consider snowfall (inches) in march is 30 inches, than monthly average is :
Monthly average snowfall= {18+38+31} / {3}= 29 inches
which is greater than 28 inches.
Therefore, If the march data on snowfall is above the average (i.e 28 inches), The monthly average will rise.