I the average score is 750 and standard deviation ( sigma ) is 50 points, then score 700 - 800 is between (750 - 1 sigma) and (750 + 1 sigma). That is 34.1 % + 34.1 % = 68.2 % of the whole population. 2,000 · 0.682 = 1.364 We expect 1,364 students to score between 700 and 800 points.
If you add all of the numerators together 3+57+13= 73 Then you would divide that number by 4 73/4= 18.25 So the course would be 18.25 or 18 1/4 miles long.
