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How do I calculate the lower class boundary and the upper class boundary for the class 40 - 59?

1 Answer
Jan 29, 2015

It depends whether your variable is discrete or continuous .

A discrete variable can only have certain values, whole numbers in your case. Think of number of students in a certain course.
If this is the case the class goes from 40 to 59, and the class midpoint will be 49.5

A continuous variable can have any value.
Think of age, where "#59#" may mean "#60# minus one minute"
In this case the upperboundary will be #59.999...# and midpoint will be #50#.

A third case is when the values have been rounded , like exam scores. There #40# would mean #39.5# and up, so that would be your lower boundary. #59# would mean up to (not including) #59.5#

So it really does depend on the kind of data that you have.