Graphs , variables and how to calculate slope > all in simplified way

1. Economics 101
John Par kin
Graphs ,variables and slope

2. Graphs in economics
• Firstly all of us we know about Graphs that
include a vertical access and horizontal axis,
vertical axis we will call “Y” axis and
horizontal axis “ X”.
• And you can called them what you want as
your prefer .
• Commone Graphs that used are :
• Time- series Graph , cross-section Graph
• And scatter Graph.

3. Time Series Graph
0
200
400
600
800
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1600
Column1
Series 2
Series 1

4. Cross- Section Graph
0 1 2 3 4 5 6
cars
housing
firms
corporations
norton
blackberry
adidas

5. Scatter Graph
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
0 0.5 1 1.5 2 2.5 3 3.5
blackberry
blackberry

6. Graphs in economics
• We use Graph to EXPLAIN economics models
in more simplified manner .
• And to show the direction of the economy in
general .
• Now I want notice you that models of
economics that we use included a variables,
these variables take different directions .

7. Types of variables
• There is variables have the same directions .
• Variables with opposite direction .
• Variables with max or min value .
• Variables are unrelated.
• Let us look at these cases :

8. Same directions variables
• In such type , the Graph shows that the tow
variables goes up and down together in same
direction and that is called “ positive
relationship “or” direct relationship” .

9. Same directions variables
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Category 1 Category 2 Category 3 Category 4
Series 3
Series 2
Series 1

10. Opposite direction Graph
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20000
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80000
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120000
140000
1 2 3 4
Series 1
Series 1

11. Unrelated variables Graph
0%
10%
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40%
50%
60%
70%
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90%
100%
12345

12. Slope of model
• We can find slope by tow ways :
1_ by the Graph , taking change in the “Y” axis
an dividing it by change in “x” axis .
2_ drive it from the model by taking the first
derivative of it .