The following is the grouped data - grades from another class of Stat 6127 (Dr. Kazemi was not the teaching this class otherwise they would have done even better!) The class midpoint is the numerical representation of the category. This means in this example in the category A=90-100, the frequency is 4. In other words, 4 people made an A which is a 95 (class midpoint) or another way of looking at it, there are four 95's, seven 85's, etc