The scatterplot above shows the revenue, in millions of dollars, that a company carned over several years and a line of best fit for the data. In Year 4 , the difference between the actual revenue and the predicted revenue is  n million dollars, where  is a posative integer. What is the value of  n ? Round your answer to the nearest whole number. (Disregard the 5 sign when gridding your answer.)

The correct answer is: 5

From the graph, we can observe that the line of best fit gives revenue 50 million dollars in year 4.
Predicted revenue in year 4 = 50 million dollars
Now, the actual revenue is the point on the vertical at year 4. It is
between 50 and 60 on the y-axis.
We consider the value to be the midpoint here, given by 
 According to the question,
The difference between the actual revenue and the predicted revenue is n million dollars,
As n is a positive integer, so we have

The value of n is 5.

Note:
As we are not certain if the point of the actual revenue is exactly at the midpoint of 50 and 60, so instead of taking the midpoint 55, we can also take it to be 54 or 56.
Then the value of n can be 4 or 6 too.