Page 3 - LN

students

Conversion of Inclusive to Exclusive form:

Consider the above classes are 10-14, 5-19,...

nd
The lower limit of 2 class (15-19)=15
The upper limit of first class(10-14)=14

The difference=15-14=1

Half of the difference=1/2=0.5

Now the converted classes are (10-0.5 - 14+0.5), (15-0.5 - 19+0.5),..........

The exclusive form of class is

Marks 9.5 – 14.5 14.5 – 19.5 19.5 – 24.5 24.5 – 29.5 29.5 – 34.5
Number of 4 6 12 5 3
students

Range: The difference between the highest and lowest observation is known as Range.

Frequency:-The observation which occurs most of the time is known as frequency.

Class Mark: For each class interval, we require a point which would serve as the
representative of the whole class.It is assumed that the frequency of each class interval
is centred around its mid-point.So the mid-point of each class interval is known as class
mark.

LOWERCLASS LIMIT  UPPERCLASS LIMIT L .L  U .L
Class mark = 
2 2

Measures of Central Tendency-There are 3 measures of central Tendency

1.Mean

2.Mode

3.Median

3