In grouped data, greatest value = 21, lowest value = 3, and number of intervals = 3, then size of class is ______?

In grouped data, greatest value = 21, lowest value = 3, and number of intervals = 3, then size of class is ______?

Explanation

To find the size of the class interval:

Size = (Greatest value - Lowest value) / Number of intervals

= (21 - 3) / 3

= 18 / 3

= 6