LEARN MATH STEP BY STEP THROUGH VERY EASY PROCESS

CUMULATIVE FREQUNCY OF A CLASS INTERVAL

**Cumulative Frequency of a Class
Interval –**

**The sum of
the frequencies of all the previous classes and that particular class, is
called or considered as the Cumulative
Frequency of the class.**

**Cumulative Frequency Table –**

**A table
which shows the cumulative frequencies over various classes is called a cumulative frequency distribution table.**

**Example.1)
Following are the ages (in years) of 360 patients, getting medical treatment in
a hospital.**

**Construct
the cumulative frequency table for the above data.**

**Ans.) The
cumulative frequency table for the above data is given below.**

**This table
may be presented in “Less than Form”, as under.**

**Example.2) The monthly wages (in rupees) of 28 labours
working in a factory are given below –**

**220,
268, 258, 242, 210, 267, 272, 242, 311, 290, 300, 320, 319, 304,302, 292, 254,
278, 318, 306, 210, 240, 280, 316, 306, 215, 256, 328. Form a cumulative
frequency table with class intervals of length 20**

**Ans.) We
may form the table as under –**