The class marks of a distribution are 26,31,36,41,46,51,56,61,66,71. Find the true class limits.

Explanation

Here,
Class size = Difference b/w any two consecutive class marks `= 31-26 = 5`
Lower limit of first class interval`=26−5/2=23.5`
Upper limit of first class interval` = 26+5/2=28.5`
Therefore, first class interval is `23.5-28.5.`
Thus, the class intervals are`:23.5−28.5,28.5−33.5,33.5−38.5,38.5−43.5,43.5−48.5,48.5−53.5`
Since, the classes are formed by exclusive method. Therefore, these limits are true class limits.