If mid value of the class interval and lower limit of the class interval are given, then upper limit of the class interval can be calculated .
If mid value of the class interval and upper limit of the class interval are given, then lower limit of the class interval can be calculated. HOW DO WE CALCULATE?
The mid value of the class is called class marks
Hence upper limit = 2 × class marks – lower limit
and lower limit = 2 × class marks – upper limit