Econometrics Assignment
. Estimate the values of β0 andβ1
Y1= β0+ β1X1+u1
Where Y1 is the dependent variable
X is the independent variable
β0 is the y intercept (the value of Y when X is zero)
β1 is the slope of the line
u1 is the residual or error term
β1= N (∑XY)-(∑X) (∑Y)/N (∑X2)- (∑X)2
β1= 10(4485) -(155) (278)/10(2453) -(155)2
β1 = 44850-43090/ 24530-24025
β1 = 1760/505
β1 = 3.49
β0 = My – β1Mx
β0 = 27.8- (15.5×3.49)
β0 = 27.8-54.095
β0 = -26.30
2. Calculate the error u1 for all the observations made
Y1 = -26.30+ 3.49X1+u1
1st observation
Replace the y and x values in the equation
22 = -26.30+ (3.49×12) + u1
22 = 15.58+ u1
U1 = 6.42
2nd Observation
38 = -26.30+(3.49×17) + u1
38 = 33.03+u1
U1 = 4.97
3rd Observation
31 = -26.30+ (3.49×16) + u1
31 = 29.54+ u1
U1= 1.46
4th Observation
15 = -26.30 + (3.49x 13) + u1
U1 = -4.07
5th Observation
20 = -26.30+ (3.49×16) + u1
U1 = -9.54
6th Observation
27 = -26.30+ (3.49×17) + u1
U1 = -6.03
7th Observation
41 = -26.30+ (3.49×19) + u1
U1 = 0.99
8th Observation
22 = -26.30+ (3.49×14) + u1
U1 = -0.56
9th Observation
43 = -26.30+ (3.49×18) + u1
U1 = 6.48
10th Observation
19 = -26.30+ (3.49×13) + u1
U1 = -0.07
Summary of the error values
Observations | Error (u1) | (u1)2 | Deviation from mean | (Deviation)2 |
1 | 6.42 | 41.22 | 3.69 | 13.62 |
2 | 4.97 | 24.70 | 2.24 | 5.02 |
3 | 1.46 | 2.13 | -1.27 | 1.61 |
4 | 4.07 | 16.56 | 1.34 | 1.80 |
5 | 9.54 | 91.01 | 6.81 | 46.38 |
6 | -6.03 | 36.36 | -8.76 | 76.74 |
7 | 0.99 | 0.98 | -1.74 | 3.03 |
8 | -0.56 | 0.31 | -3.29 | 10.82 |
9 | 6.48 | 41.99 | 3.75 | 14.06 |
10 | -0.07 | 0.00 | -2.8 | 7.84 |
Mean | 2.73 | |||
Sum | 255.26 | 180.92 |
3. Calculate and interpret the standard error of regression
The formula for calculating the regression error is Standard Error = √Sum of error squared/number of observations
The error values give the distance between the actual data points and the regression line. The regression error evaluates the precise nature of the model in predictions based on the dependent variable units. A smaller value of the standard error signifies a lower distance between the regression line and the data points and is therefore desired. A smaller value indicates that the model is sufficiently precise.
The standard error of regression for the sample is calculated below
Standard Error = 5.05
The value obtained is relatively high, thus it can be concluded that the model is not highly sufficient in making the predictions.
4. Calculate and interpret the standard error for B1
Standard Error = 1.10
5. Test the null hypothesis H0:B1=0 (p=0.05)
Test statistics = x-µ/SD/√n
SD = 9.43
Test Statistics = (27.8-0)/(9.43/3.16)
Test Statistics = 9.32
The z score falls outside the range, justifying the rejection of the null hypothesis.
Therefore, there is no sufficient evidence to accept the hull hypothesis
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