Thomas Robert Malthus
WELCOME
BY: - RAMESH KUMAR,
PGT – ECONOMICS,
K V NO.1, BATHINDA CANTT.
CONCEPTUAL QUESTIONS: -
1. What is relationship between height and weight?
2. What is relation between age of husband and wife?
3. What is the relationship between price and demand?
What do you Mean by correlation?
Meaning of Correlation
Correlation is a statistical tools which shows the relationship between the two variables in which change in the value of one variable due to change in the value of other variable
KINDS OF CORRELATION
• Positive and Negative correlation
• Linear and Non Linear Correlation.
• Simple, Multiple and Partial Correlation.
Positive and Negative correlation
When both the variable change in the same direction, i.e. both the variables increase or both the variables decrease, it is called Positive Correlation
POSITIVE CORRELATION
Both Variables increasing
• X Y
• 10 100
• 20 150
• 30 160
• 40 190
• 50 200
• 60 255
Both Variables Decreasing
• X Y
• 70 147
• 60 140
• 40 135
• 30 130
• 15 120
• 10 90
What is negative Correlation?
Negative Correlation
When both variable change in the opposite direction, it is called Negative correlation.
NEGATIVE CORRELATION
One Variable increasing and other Decreasing
• X Y
• 25 125
• 30 110
• 35 90
• 40 80
• 45 75
• 50 60
One variable Decreasing , the other increasing
• X Y
• 75 110
• 60 180
• 40 190
• 30 300
• 20 240
• 10 250
ACTIVITY FOR THE STUDENTS
Please write down: -
(A) 4 example of Positive Correlation and
(B) 4 examples of negative Correlations
Examples of Positive and Negative Correlation
POSITIVE CORRELATION:-
1. Age of Husband & Age of wife
2. Price of commodity and amount of supply.
3. Increase in heat affects temperature.
4. Increase in height and weight.
NEGATIVE CORRELATION: -
1. Demand of commodity may go down a aresult of rise in prices.
2. Sale of woollengarments and day temperature.
3. Yield of crops and price.
Linear correlation and Non Linear Correlation
* If the Ratio of change between two variables is uniform than Linear correlation exists.
* linear and Non – Linear correlation is based upon the consistency of the ratio of changes between the variables.
* Their relationship described by straight line
If the variables under study are graphed, the point will form a straight line,
LINEAR CORRELATION
• In case of non linear relationship , the amount of change in one variable does not bear a constant ratio to the amount of change in the other variable, Such as relationship will form a curve on graph.
Non Linear Correlation
If the ratio of change between the variable is not the same than Non linear correlation exists. Non –Linear Relationship will form curve on graph.
Simple Correlation
Simple Correlation : - It is based upon the number of variable under study.
• When only two variables are studied, the correlation between them is called simple Correlation
Multiple and Partial Correlation
When three or more variables are studied the relationship can be either multiple or partial.
DEGREE OF CORRELATION
There is three types of correlations: -
1. Perfect Correlation.
2. Zero Correlation.
3. Limited degree Correlation.
PERFECT DEGREE OF CORRELATION: -
• Perfect degree correlation is that where changes in two variables are exactly proportional. If equal proportion changes are in the same direction, there is perfect positive correlation between the two values described as + 1,
• If equal proportional changes are in the reverse direction, there is perfect negative correlation, described as -1.
ZERO DEGREE CORRELATION
• The value of Coefficient of correlation may be zero. It means that there is zero correlation.
• It does not mean the absence of any type of relation between the two variables. Two value are uncorrelated . However, other type of relation may be there. There is no Linear relationship between them.
LIMITED DEGREE CORRELATION
• In social science , the variables may be correlated, but an increase in one variable need not always be accompanied by a corresponding or equal increase (or decrease) in the variableS.
• Correlation said to be limited positive when there are unequal's changes in the two variables in the same direction and correlation degree of combination can be high ( between + 0.75 to 0.99 and - 0.75 to -0.99)
• Moderate ( + 0.25 to + 0.74 and -0.25 to -0.74)• Low degree correlation 0 to + 0.24 and 0 to -0.24)
-
DEGREE OF CORRELATION
PERFECT CORRELATION
NO CORRELATION
-1
POSITIVE OPERFECT
+1
DEGREE OF CORRELATION
LIMITED DEGREE CORRELATION
NEGATIVEPOSITIVE
LIMITED DEGREES OF CORRELATION
HIGH
+ 0.75 TO 0.99
-.075 TO -0.99
MODERATE
+0.25 TO + 0.74
-0.25 TO – 0.74
LOW
+0 TO +0.24
0 TO -0.24
RECAPTULATION : -
• 1. What is correlation?
2. What is Positive Correlation?
3. What do you mean negative correlation?
4. What is Simple correlation?
5. What is meant by Multiple Correlation?
HOME ASSIGNMENT
• What is meant by Correlation?
• What are different types of correlation? Show with the help of example of daily life.
• PROJECT: - Calculate Correlation between History and Economics, Economics and Maths. of the students of your group on the basis of First Term Unit Test Marks.
• Correlation with other subjects.
Thanks
RAMESH KUMAR,
PGT ECONOMICS,
K V NO.1, BATHINAD CANTT.
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