# Organisation of Data in Statistics class 11 Notes PDF Free Downlo

Chapter 3 Organization Of Data

## 1. Classification of Data :-

The process of grouping data according to their characteristics is known as classification of data.

2. Objectives of Classification :-

a] To simplify complex data
b] To facilitate understanding
c] To facilitate comparison
d] To make analysis and interpretation easy.
e] To arrange and put the data according to their common characteristics.

3. Statistical Series :-

Systematic arrangement of statistical data

I. Can be on the basis of individual units :- The data can be individually presented in two forms:

i] Raw data : Data collected in original form.
ii] Individual Series : The arrangement of raw data individually. It can be expressed in two ways.
a] Alphabetical arrangement : Alphabetical order
b] Array :
Ascending or descending order.

II. Can be on the basis of Frequency Distribution :- Frequency distribution refers to a table in which observed values of a variable are classified according to their numerical magnitude.

1. Discrete Series :-

A variable is called discrete if the variable can take only some particular values.

2. Continuous Series :-

A variable is called continuous if it can take any value in a given range. In constructing continuous series we come across terms like:

a] Class : Each given internal is called a class e.g., 0-5, 5-10.
b] Class limit : There are two limits upper limit and lower limit.
c] Class interval :
Difference between upper limit and lower limit.
d] Range :
Difference between upper limit and lower limit.

e] Mid-point or Mid Value :

f] Frequency :
Number of items [observations] falling within a particular class.

i] Exclusive Series : Excluding the upper limit of these classes, all the items of the class are included in the class itself. E.g., :

ii] Inclusive

 Marks 0-10 10-20 20-30 30-40 Number of Students 2 5 2 1

Series : Upper class limits of classes are included in the respective classes. E.g.,

 Marks 0-9 10-19 20-29 Name of Students 2 5 2

##### Open End Classes :

The lower limit of the first class and upper limit of the last class are not given. E.g.,

 Marks Below 20 20-30 30-40 40-50 50 and above Number of Students 7 6 12 5 3

iii] Cumulative Frequency Series : It is obtained by successively adding the frequencies of the values of the classes according to a certain law.
a] ‘Less than’ Cumulative Frequency Distribution : The frequencies of each class-internal are added successively.
b] ‘More than’ Cumulative Frequency Distribution : The more than cumulative frequency is obtained by finding the cumulative totals of frequencies starting from the highest value of the variable to the lowest value.

 Marks No. of Students 0-10 2 10-20 5 20-30 10 30-40 12 40-50 17 50-60 4

 Marks No. of Students Less than 10 2 Less than 20 7 Less than 30 17 Less than 40 29 Less than 50 46 Less than 60 50
 Marks No. of Students More than 0 50 More than 10 48 More than 20 43 More than 30 33 More than 40 21 More than 50 4

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