To Ogive Diagram

Ogive plot is also known as cumulative frequency plot.

Information Obtatined By Ogive Diagram:-

Following are the information that can be obtained by using ogive plot from a set of grouped data.

Median
Lower quartiles or lower median.
Upper quartile or upper median.
Inter quartile range.

With the ogive plot the box plot can also be drawn.

Calculating cumulative frequency is the first step in drawing ogive plot.Cumulative frequency is the running sum of their frequencies.

The ogive plot drawn with cumulative frequency  vs. upper class boundary or lower class boundary.

ogive
Types of Ogive Diagrams:-

There are two types of ogive plots

Less than ogive
More than ogive.

Less Than Ogive:-
The this type cumulative frequencies are in ascending order and they are plotted against upper class boundary.

More Than Ogive:-

The this type cumulative frequencies are in descending order and they are plotted against lower class boundary.
Example Problem:-

The following set of data that shows the marks obtatined by the students in a exam. Draw the more than ogive and lessthan Ogive diagram for the following data .

Solution:-

The intial step to draw ogive diagram is to calculate the cumulative frequency.

Less than ogive help:-

ogive

Note

The frequencies are added, as pointed out by the arrows, to obtain the cumulative frequency.
In the table shown above, it can be noted that 20 students scored marks  'less than 10', 29 students scored marks 'less than 20' and so on.

Hence, the over distribution is called 'less than' ogive diagram.ogive

Morethan Ogive help:-

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Note

The frequencies are added, as pointed out by the arrows, to obtain the cumulative frequency.
In the table shown above, it can be noted that 20 students has scored marks 'more than 40', 32 students have scored marks 'more than 30' and so on.
Hence, the over distribution is called 'more than' ogive plot.

ogive