Ok, here are the steps to determine how many points should be below the trend line:
1) There are 4 points above the trend line.
2) If the points are distributed randomly and evenly on both sides of the trend line, then there should be approximately the same number of points above and below the line.
3) Since there are 4 points above the line, there should be around 4 points below the line as well.
Therefore, the answer is that about 4 points should be below the trend line.