presentation econometrics ex 1.pdf

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EX.1
The table below presents data from supermarket on monthly sales of apples ( A ,
in tones per month), average apples prices ( P A , in PLN/kg) and average
oranges prices ( P O , in PLN/kg) in the period August 2008 – January 2009.
t
A
P A
P O
1
6
1
7
2
6
2
6
3
4
3
6
4
3
4
5
5
2
5
4
6
3
5
3
835956439.127.png 835956439.138.png 835956439.149.png 835956439.160.png 835956439.001.png 835956439.012.png 835956439.023.png 835956439.033.png 835956439.044.png 835956439.055.png 835956439.065.png 835956439.076.png 835956439.086.png 835956439.087.png 835956439.088.png 835956439.089.png 835956439.090.png 835956439.091.png 835956439.092.png 835956439.093.png 835956439.094.png 835956439.095.png 835956439.096.png 835956439.097.png 835956439.098.png 835956439.099.png 835956439.100.png 835956439.101.png 835956439.102.png 835956439.103.png 835956439.104.png 835956439.105.png 835956439.106.png 835956439.107.png 835956439.108.png 835956439.109.png 835956439.110.png 835956439.111.png 835956439.112.png 835956439.113.png 835956439.114.png 835956439.115.png 835956439.116.png 835956439.117.png
 
a)
What kind of relationship do You expect between the demand on apples
and the prices of apples and oranges?
When P A then A
When P A then A
There is negative relationship between the prices of apples and demand on them.
When P O then A
When P O then A
There is positive relationship between prices of oranges and demand on apples
b)
Estimate parameters of the model:
A = β 0 + β 1 *P A + β 2 P 0 + ε
Interpret the results.
6
PA
PO
1
1
7
6
1
2
6
Y =
4
X =
1
3
6
3
1
4
5
2
1
5
4
3
1
5
3
835956439.118.png 835956439.119.png 835956439.120.png 835956439.121.png 835956439.122.png 835956439.123.png 835956439.124.png 835956439.125.png 835956439.126.png 835956439.128.png 835956439.129.png 835956439.130.png 835956439.131.png 835956439.132.png 835956439.133.png 835956439.134.png 835956439.135.png 835956439.136.png 835956439.137.png 835956439.139.png 835956439.140.png 835956439.141.png 835956439.142.png 835956439.143.png 835956439.144.png 835956439.145.png 835956439.146.png 835956439.147.png 835956439.148.png 835956439.150.png 835956439.151.png 835956439.152.png 835956439.153.png 835956439.154.png 835956439.155.png 835956439.156.png 835956439.157.png 835956439.158.png 835956439.159.png 835956439.161.png 835956439.162.png 835956439.163.png 835956439.164.png 835956439.165.png 835956439.166.png 835956439.167.png 835956439.168.png 835956439.169.png 835956439.170.png 835956439.002.png 835956439.003.png 835956439.004.png 835956439.005.png 835956439.006.png 835956439.007.png 835956439.008.png 835956439.009.png 835956439.010.png 835956439.011.png 835956439.013.png 835956439.014.png 835956439.015.png 835956439.016.png 835956439.017.png 835956439.018.png 835956439.019.png 835956439.020.png 835956439.021.png 835956439.022.png 835956439.024.png 835956439.025.png 835956439.026.png 835956439.027.png
Few steps to estimate parameters:
1. X T
2. X T X
3. det. (X T X)
4. (X T X) -1
5. X T Y
6. b=(X T X) -1 * X T Y
1.
X T =
1
1
1
1
1
1
1
2
3
4
5
5
7
6
6
5
4
3
X T X =
6
20
31
2.
20
80
92
31
92
171
835956439.028.png
 
835956439.029.png 835956439.030.png 835956439.031.png 835956439.032.png 835956439.034.png 835956439.035.png 835956439.036.png 835956439.037.png 835956439.038.png 835956439.039.png 835956439.040.png 835956439.041.png 835956439.042.png 835956439.043.png 835956439.045.png 835956439.046.png 835956439.047.png 835956439.048.png 835956439.049.png 835956439.050.png 835956439.051.png 835956439.052.png 835956439.053.png 835956439.054.png 835956439.056.png 835956439.057.png
 
3. det. (X T X) 0
The result is 96 so it’s okay.
4.
(X T X) -1 = 54,3333
-5,9167
-6,6667
-5,9167
0,6771
0,7083
-6,6667
0,7083
0,8333
5.
X T Y =
24
67
134
6. b= (X T X) -1 * X T Y
b =
14,25
-1,71875
-0,875
835956439.058.png 835956439.059.png 835956439.060.png 835956439.061.png 835956439.062.png 835956439.063.png 835956439.064.png 835956439.066.png 835956439.067.png 835956439.068.png 835956439.069.png 835956439.070.png 835956439.071.png 835956439.072.png 835956439.073.png 835956439.074.png 835956439.075.png 835956439.077.png 835956439.078.png 835956439.079.png 835956439.080.png 835956439.081.png 835956439.082.png 835956439.083.png 835956439.084.png 835956439.085.png
Zgłoś jeśli naruszono regulamin