You can find the midpoint of each class by adding the lower class limit and the upper class limit, then dividing by two: Class midpoint = (lower

Find the midpoint and the margin or error. That is write this interval in the form: \[a\pm b\] Solution. Let's first find the midpoint. This is the average of the left and right

Find the Midpoints of the Frequency Table. Class Frequency 90 − 99 4 80 − 89 6 70 − 79 4 60 − 69 3 50 − 59 2 40 − 49 1 Class Frequency 90 - 99 4 80 - 89 6 70 - 79 4 60 - 69 3 50 - 59 2 40 - 49 1.