# Frequency Curve – Diagrammatic and Graphical Representation of Data

## Reference Notes Unit: Statistics | Economics Frequency Curve Graphs of Frequency Distribution Management: Class 11

Frequency Curve
If we join the vertices of the frequency polygon by freehand, then the curve so drawn is called frequency curve. It is a smooth and regular curve without any sharp turns. The area under the frequency curve, frequency polygon and histogram should be equal. It should be carefully drawn.

Example:

 Marks 5 – 10 10 – 15 15 – 20 20 – 25 25 – 30 No. of students 2 5 4 8 3 Ogive or cumulative frequency curve:
There are two types of cumulative frequency curves.

a) “Less than” cumulative frequency curve: these curves are drawn by using the “less than” values of the variable and their corresponding frequencies in “less than” cumulative distribution of data.

Example:
Draw the “less than” frequency curve of the following data:

 Price of shares (Rs.) 50 – 100 100 – 150 150 – 200 200 – 250 250 – 300 300 – 350 No. of shares 15 20 22 21 10 5

Solution:
Converting the data into “less than” frequency

 Price of share (Rs.) Cumulative frequency Less than 100 15 Less than 150 35 Less than 200 57 Less than 250 78 Less than 300 88 Less than 350 93 b) “More than” cumulative frequency curve: These curves are drawn by using the more than values of the variables and their corresponding frequencies in “more than” cumulative distribution of data.

Example:
“More than” frequency of the above share data is

 Price of share (Rs.) Cumulative frequency More than 50 93 More than 100 78 More than 150 58 More than 200 36 More than 250 15 More than 300 5 Posted By : | Comment RSS | Category : Class XI, HSEB Notes