Adjusted R2 F Statistic 293002
1. **State the problem:**
We are given a regression model with sample size $n=8$, $R^2=0.937$, and an ANOVA table. We need to find the adjusted $R^2$ (denoted $\bar{R}^2$) and the F-statistic for the model.
2. **Recall formulas:**
- Adjusted $R^2$ is calculated by:
$$\bar{R}^2 = 1 - \frac{(1-R^2)(n-1)}{n-p-1}$$
where $p$ is the number of predictors.
- The F-statistic for the model is:
$$F = \frac{\text{MS}_{\text{Regression}}}{\text{MS}_{\text{Residual}}}$$
3. **Identify values:**
- $n = 8$
- $R^2 = 0.937$
- From the ANOVA table, Regression degrees of freedom $DF_{Regression} = 2$ (so $p=2$ predictors)
- Mean Square Regression $MS_{Regression} = 10.5128$
- Mean Square Residual $MS_{Residual} = 0.2846$
4. **Calculate adjusted $R^2$:**
$$\bar{R}^2 = 1 - \frac{(1-0.937)(8-1)}{8-2-1} = 1 - \frac{0.063 \times 7}{5} = 1 - \frac{0.441}{5} = 1 - 0.0882 = 0.9118$$
Rounded to three decimals: $\bar{R}^2 = 0.912$
5. **Calculate F-statistic:**
$$F = \frac{10.5128}{0.2846} = 36.93$$
6. **Interpretation:**
- The adjusted $R^2$ accounts for the number of predictors and sample size, providing a more unbiased estimate of model fit.
- The F-statistic tests whether the regression model explains a significant amount of variance compared to residual error.
**Final answers:**
- Adjusted $R^2 = 0.912$
- $F_{model} = 36.93$