Simple cross validation

<p>This workflow is designed to illustrate how to estimate test error using cross validation.</p><p>The workflow reads in the dataset, splits it into training and test sets multiple times (cross-validation), trains a <strong>polynomial regression model</strong> on each training set, predicts outcomes on the corresponding test set, and then evaluates prediction accuracy. By repeating this process for different model complexities, it helps identify which model best balances <strong>fit</strong> and <strong>generalization</strong>, reducing the risk of overfitting.</p>