164 The Basics of financial economeTrics
Let’s illustrate the robustness of regression through another example.
Let’s create an equally weighted index with the daily returns of 234 Japanese
firms. Note that this index is created only for the sake of this illustration;
no econometric meaning is attached to this index. The daily returns for the
index for period 1986 to 2005 are shown in Figure 8.1.
Now suppose that we want to estimate the regression of Nippon Oil on
this index; that is, we want to estimate the following regression:
RNO = β 0 + β 1 RIndex + Errors
Estimation with the standard least squares method yields the following
regression parameters:
R^2 : 0.1349
Adjusted R^2 : 0.1346
Standard deviation of errors: 0.0213
Beta t-Statistic p-Value
β 0 0.0000 0.1252 0.9003
β 1 0.4533 27.6487 0.0000
0
–0.2
–0.15
–0.1
–0.05
0
0.05
0.1
0.15
500 1000 1500 2000 2500
Days
Returns
3000 3500 4000 4500 5000
FIGURE 8.1 Daily Returns of the Japan Index: 1986–2005