NIOS STD X Economics Chapter 17 & 18 Collection, Presentation and analysis of Data

1. Collection and presentation of data

2. My task
• As a teacher I have a Purpose.
• My purpose is to teach you and make sure you
do well in the exams
• For this I need to know your level, your strength
and weakness
• To understand this I will keep testing you.
• Based on the results I get I will know how to
help you.

3. Test done results received
Sameeha Iyer 32
This is the marks of Sameeha.
I cannot take any action based on this because I don’t know the marks of other
students.
So this is only a fact and not a data.
To take any action I need DATA.
Data means quantitative information which is expressed as a total.
For example – data about income, population, prices etc.
Data is also called statistical data or statistics.
Data is the total of all students in the class.
Marks of one student is only a Fact.

4. Test done results received
Sr. No Name Marks
1 Abdur Rahman 32
2 Aliarsh 18
3 Angad 45
4 Chinmay 33
5 Deepak H 18
6 Devinder Jeet 25
7 Dilona F 21
8 Eliza F 37
9 Hari Santosh 16
10 Hari Shankar 16
11 Heena Momin 24
12 Hitendra D 20
13 Manas Shah 22
14 Mayur Shetty 18
15 Megha R.P 26
16 Nikita .V 37
17 Omkar Patil 37
18 Pooja Sharma 26
19 Sameeha Iyer 32
20 Shivam Rawat 16
21 Shruti mugul 34
22 Shruti P 21
23 Tabish 16
24 Tamana Mallick 38
25 Taniya Yadav 42
26 Tanvi Kokare 31
The characteristics of data are –
1) Statistics are aggregates of facts.
2) They are expressed as numbers.
3) Data can be affected by a number of causes.
4) It does not give 100 % accuracy.
5) Data is collected for a predetermined
purpose.
Now I have the marks of all the students.

5. Importance of Data in economics ….
• In economic planning: To prepare a future plan we need the data of the previous
year.
• If we need to plan the expenditure for education for a year we need data regarding
number of students, expenditure incurred etc. Based on these data’s we can plan for
the coming year.
• To determine National income : In order to know the state of our economy it is
important to know the national income.
• To know the national income we need to get information on the total wages
received by all workers, rent received , interest received and profits earned by the
entrepreneur in the given year.
• Government policies : Statistical data are used by government to frame policies for
economic development of the country. In India Census is carried out once in every
10 years. This provides the government data of the total population, number of
literates, number of employed people, number of old people… Based on this the
government makes its policies.

6. Types of Data
• Primary data.
• Data which is collected for the first time for a
particular purpose is called Primary data.
• Secondary data. When we use data that has
already been collected by others then it is called
Secondary data.

7. • There are five methods of collecting primary data. They are –
• 1) Direct personal investigation.
• 2) Indirect investigation.
• 3) Through correspondents.
• 4) By mailed questionnaire.
• 5) Through schedules.

8. • Secondary Data may exist in the form of
Published or unpublished form.
• Published form it can be got/obtained from
– Reports in newspapers, periodicals, RBI.
– trade associations
– SEBI publication
– Official publications
– International bodies like UNO, World bank etc.
• Unpublished form may exist as
⁻ Internal reports of the government
⁻ Records maintained by institutes
⁻ Reports prepared by students

9. Presentation of Data
• Data collected are in the form of raw material.
• To make use of them they need to be arranged,
organised.
• Classification and Tabulation are the basic tools
of presenting raw data.
• Classification is a process of arranging data into
classes or groups.

10. Variables and Attributes
• Variable
• 1) When data can be classified in terms of time or
size, it is called variable.
• 2) For example – height, eight, length, distance etc.
• Attribute
• 1) Data which cannot be classified in terms of time
or size is called attribute.
• 2) For example – beauty, bravery, intelligence etc.

11. Name Marks
Abdur Rahman 32
Aliarsh 18
Angad 45
Chinmay 33
Deepak H 18
Devinder Jeet 25
Dilona F 21
Eliza F 37
Hari Santosh 16
Hari Shankar 16
Heena Momin 24
Hitendra D 20
Manas Shah 22
Mayur Shetty 18
Megha R.P 26
Nikita .V 37
Omkar Patil 37
Pooja Sharma 26
Sameeha Iyer 32
Shivam Rawat 16
Shruti mugul 34
Shruti P 21
Tabish 16
Tamana Mallick 38
Taniya Yadav 42
Tanvi Kokare 31
Raw Data
Sr. No Name Marks
3 Angad 45
25 Taniya Yadav 42
24 Tamana 38
16 Nikita .V 37
8 Eliza F 37
17 Omkar Patil 37
21 Shruti mugul 34
4 Chinmay 33
1 Abdur Rahman 32
19 Sameeha Iyer 32
26 Tanvi Kokare 31
15 Megha R.P 26
18 Pooja Sharma 26
6 Devinder Jeet 25
11 Heena Momin 24
13 Manas Shah 22
7 Dilona F 21
22 Shruti P 21
12 Hitendra D 20
2 Aliarsh 18
5 Deepak H 18
14 Mayur Shetty 18
9 Hari Santosh 16
10 Hari Shankar 16
20 Shivam Rawat 16
23 Tabish 16
Arranged descending
order
individual series.
Arranged
Discrete
series
Marks
No. of
students
16 4
18 3
20 1
21 2
22 1
24 1
25 1
26 2
31 1
32 2
33 1
34 1
37 3
38 1
42 1
45 1
X F
0 - 10 -
10 - 20 8
20 - 30 7
30- 40 9
40 - 50 2
X = Groups
F = Frequency
Arranged
Continuous series
Individual, Discrete and continuous Series

12. Tabulation
• Tabulation – Once data is collected and
classified, it can be put into rows and columns.
• This Process is called tabulation.

13. Diagrammatic presentation
• Diagrammatic presentation – The geometrical version of
data is diagrammatic presentation.
• Example – bar diagram is a one dimensional diagram.

14. Analysis of Data

15. • Analysis of Data
• After Data has been collected, classified,
tabulated and presented, it is studied to reach a
conclusion.
• This is called analysis of data.
• Central tendency
• The tendency of data to group around the
central value or valve is called central tendency.

16. Arithmetic Mean
• Arithmetic mean is one of the methods of calculating central tendency.
• It is an average.
• It is calculated to reach a single value which represents the entire data.
• Calculating an Average
• For example (1, 2, 2, 2, 3, 9). The arithmetic mean is
1 + 2 + 2 + 2 + 3 + 9
6 = 19/6 = 3.17
• Arithmetic means are used in situations such as working out cricket
averages.
• Arithmetic means are used in calculating average incomes.

17. Calculation of Arithmetic Mean Individual Series
First method : Direct Method
No. of marks got by 10 students
out of 30 x
= ∑x/N 4
3
∑x = sum total no. of observations 8
9
N = Total no. of students 12
10
4+3+8+9+12+10+25+21+20 25
10 10
= 12.2 21
20
Calculation of Arithmetic mean for Individual Series:

18. No. of marks got by 10 students
out of 30 (x)
4
3
8
9
12
10
25
10
21
20
1. Assume a Mean (A)
2. Let us say the assumed mean(A) is 12
3. Formula = A + ∑dx/N ( ∑dx= is total of dx; N is the total no. of students)
dx= x-A ( in this case since A= 12 it is x-12)
Arithmetic mean = A + (Total of all dx i.e ∑dx divided by total no. of students)
12 + 2/ 10 = 12 + 0.2 = 12.2
dx
4 - 12
3 - 12
8 - 12
9 -12
12 -12
10 -12
25-12
10-12
21-12
20 -12
∑dx
dx= x-12
-8
-9
-4
-3
0
-2
13
-2
9
8
∑dx 2
= A + ∑dx/N =
Calculation of Arithmetic mean for Individual Series: Shortcut Method

19. Discrete Series : Direct Method
Number of Children per family
x
0
1
2
3
4
5
6
Number of families having x no.
of children
f
13
17
20
40
20
17
13
fx
13 x 0
17 x 1
20 x 2
40 x 3
20 x4
17 x 5
13 x 6
∑fx =
fx
0
17
40
120
80
85
78
∑f = 140 ∑fx = 420
∑f = Total of f
∑ fx = Total of fx
Arithmetic Mean =
= ∑fx/∑f
= 420/140 =3

20. Discrete Series : Shortcut Method
x= Number of children per family
f = Number of families
A = 2
N= Total number of families
x
0
1
2
3
4
5
6
f
13
17
20
40
20
17
13
∑f = 140
dx = (x-A)
(A=2)
-2
-1
0
1
2
3
4
fdx
-26
-17
0
40
40
51
52
∑fdx= 140
= A +∑fdx/∑f
= 2 + 140/ 140
= 2+1
= 3
Arithmetic mean =

21. Continuous Series : Direct Method
x
(Marks
0-10
10-20
20-30
30-40
40-50
50-60
60-70
Mid Value
L1+L2 /2
0+10/2 5
10+20/2 15
20+30/2 25
30+40/2 35
40+50/2 45
50+60/2 55
60+70/2 65
f ( no. of
students)
23
27
40
120
40
27
23
∑f = 300
fx
23 x5
27x 15
40x25
120x35
40 x 45
27 x 55
23 x65
∑fx =
Step 1 = take the mid value for each
class
= Lower class + upper class /2
= L1 +L2/2
Step 2 = Multiply f with the mid value
to get fx
Arithmetic mean =
= ∑fx/ ∑f = 35= 10500/ 300
115
405
1000
4200
1800
1485
1495
10500

22. Continuous Series : Shortcut Method
Without step deviation
Marks
0-10
10-20
20-30
30-40
40-50
50-60
60-70
Mid Value
L1+L2 /2 (x)
0+10/2 5
10+20/2 15
20+30/2 25
30+40/2 35
40+50/2 45
50+60/2 55
60+70/2 65
f ( no. of
students)
23
27
40
120
40
27
23
∑f = 300
dx = x -A
(A=25)
5-25 -20
15-25 -10
25-25 0
35-25 10
45-25 20
55-25 30
65-25 40
fdx
23 x -20 -460
10 x 27 -270
0 x 40 0
10 x 120 1200
20 x 40 800
30 x 27 810
40 x 23 920
∑fdx = 3000
Step 1 = take the mid value for each class = Lower class + upper class /2
= L1 +L2/2
Step 2 = Assume A = 25
Step 3= find dx = x -A
Step 4 = Multiply f x dx
Step 5 = find ∑f
total of f
∑fdx = total of fdx
Step 6 =
Step 7 find
arithmetic mean
= A + ∑fdx/ ∑f
= 25 +3000/300
= 35

23. Continuous Series : Shortcut Method
Without step deviation
= A + ∑fdx/ ∑f x c