These notes for CBSE Class 11 Economics, Chapter 3, focus on the Organization of Data. They explain the process of classification, which involves grouping data based on common characteristics to simplify complexity, facilitate understanding, comparison, and analysis. The notes detail statistical series, including individual series (raw data, alphabetical arrangement, array) and frequency distribution. Frequency distribution is further broken down into discrete and continuous series. For continuous series, key terms like class, class limit, class interval, range, mid-point, and frequency are defined. Different types of continuous series are discussed: exclusive, inclusive, open-end classes, and cumulative frequency series ('less than' and 'more than'). These notes provide a clear overview of data organization techniques essential for statistical analysis and are ideal for exam revision.
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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
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
Classification of data is the process of grouping data according to their common characteristics to simplify complex information and facilitate understanding and analysis. The main objectives are to simplify complex data, facilitate understanding and comparison, and make analysis and interpretation easier. A statistical series is a systematic arrangement of statistical data, which can be based on individual units or frequency distribution. A discrete series involves a variable that can take only specific values, while a continuous series involves a variable that can take any value within a given range. Class limits are the upper and lower bounds of a class (e.g., 0-5), and the class interval is the difference between the upper and lower limits (e.g., 5). A cumulative frequency series is obtained by successively adding the frequencies of classes, either in a 'less than' or 'more than' format. An open-end class is a class where either the lower limit of the first class or the upper limit of the last class is not specified.
Frequently asked questions
What is classification of data in statistics?
What are the main objectives of classifying data?
What is a statistical series?
What is the difference between discrete and continuous series?
What are class limits and class intervals in a continuous series?
What is a cumulative frequency series?
What is an open-end class?
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