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.