
Explanation:
The correct answer is D.
The correlation matrix shows extremely high pairwise correlations among the three independent variables (the equity indexes):
These values (especially the near-perfect 0.998 between Russell 1000 and Russell 3000) indicate multicollinearity—a situation in multiple regression where the independent variables are highly linearly related to one another. Multicollinearity is a classic violation of OLS regression assumptions and leads to several issues visible here:
In FRM Part 1 (Quantitative Analysis section), multicollinearity is detected precisely by high correlations among regressors combined with a high overall R² but individually insignificant coefficients. This is an example of imperfect multicollinearity (not perfect, since correlations are not exactly 1.0).
A: The coefficient 0.3533 on Russell 3000 is the largest in magnitude, but statistical significance is determined by the t-statistic (or p-value), not the size of the coefficient. Here, its t-stat is only 0.204 with a p-value of 0.8382—insignificant, and actually less "significant" than the Russell 2000 coefficient (t-stat 0.762). The large coefficient size is likely an artifact of multicollinearity distorting the estimates.
B: A high Adjusted R² (0.9) shows that the model as a whole explains a large portion of the variation in portfolio returns. However, it does not imply that the individual coefficients are statistically significant. In fact, multicollinearity often produces exactly this pattern: strong overall fit but insignificant individual t-tests.
C: A high p-value (0.9452 for Russell 1000) indicates the coefficient is less statistically significant (we cannot reject the null hypothesis that the true coefficient is zero). Lower p-values mean higher significance. All three p-values are high, confirming insignificance across the board.
This question tests your ability to interpret regression diagnostics beyond just R² and to recognize multicollinearity from both the correlation matrix and the pattern of insignificant coefficients. Focus on similar examples in GARP practice exams, as this is a recurring topic.
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A risk manager has estimated a regression of a firm’s monthly portfolio returns agains the returns of three U.S. domestic equity indexes: the Russell 1000 index, the Russell 2000 index, and the Russell 3000 index. The results are shown below.
| Variable | Coefficients | Standard Error | t-Stat | P-value |
|---|---|---|---|---|
| Intercept | 0.0023 | 0.0006 | 3.530 | 0.0005 |
| Russell 1000 | 0.1093 | 1.5895 | 0.068 | 0.9452 |
| Russell 2000 | 0.1055 | 0.1384 | 0.762 | 0.4470 |
| Russell 3000 | 0.3533 | 1.7274 | 0.204 | 0.8382 |
| Portfolio Returns | Russell 1000 | Russell 2000 | Russell 3000 | |
|---|---|---|---|---|
| Portfolio | 1.000 | 0.937 | 0.856 | 0.945 |
| Russell 1000 | 0.937 | 1.000 | 0.813 | 0.998 |
| Russell 2000 | 0.856 | 0.813 | 1.000 | 0.845 |
| Russell 3000 | 0.945 | 0.998 | 0.845 | 1.000 |
Based on the regression results, which statement is correct?
A
The estimated coefficient of 0.3533 indicates that the returns of the Russell 3000 index are more statistically significant in determining the portfolio returns than the other two indexes.
B
The high adjusted R² indicates that the estimated coefficients on the Russell 1000, Russell 2000, and Russell 3000 indexes are statistically significant.
C
The high p-value of 0.9452 indicates that the regression coefficient of the returns of Russell 1000 is more statistically significant than the other two indexes.
D
The high correlations between each pair of index returns indicate that multicollinearity exists between the variables in this regression.