Answer
$R^2=0.8160=81.60$%
81.60% of the variation of the annual income is explained by the model found in part (b).
$R^2_{adj}=0.7751=77.51$%
It adjusts the value of $R^2$, given the size of the sample, n, and the number of explanatory variables, k.
Work Step by Step
See the results in MINITAB, part (b).
$R^2=0.8160=81.60$%
$R^2_{adj}=1-(\frac{n-1}{n-k-1})(1-R^2)=1-(\frac{12-1}{12-2-1})(1-0.8160)=0.7751$
