Organisation Of Data In Statistics Class 11 Notes PDF Free Download
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., 05, 510.
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] Midpoint 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 
010  1020 
2030 
3040 
Number of Students  2  5  2  1 
Series : Upper class limits of classes are included in the respective classes. E.g.,
Marks 
09 
1019 
2029 
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  2030  3040  4050  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] â€˜Less thanâ€™ Cumulative Frequency Distribution : The frequencies of each classinternal are added successively.
b] â€˜More thanâ€™ 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.



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