diff --git a/docs/en/getting-started/quickstart-guide.md b/docs/en/getting-started/quickstart-guide.md
index a58340a5..79f8f955 100644
--- a/docs/en/getting-started/quickstart-guide.md
+++ b/docs/en/getting-started/quickstart-guide.md
@@ -216,7 +216,7 @@ ee = compute_residues_autocorrelation(y_valid, yhat)
 plot_residues_correlation(data=ee, title="Residues", ylabel="$e^2$")
 
 # Compute and plot cross-correlation between residuals and an input
-x1e = compute_cross_correlation(y_valid, yhat, x2_val)
+x1e = compute_cross_correlation(y_valid, yhat, x_valid)#The final argument was previously x2_val, which was not defined in the example. Updated it to x_valid (the correct validation input) so the code runs without errors.
 plot_residues_correlation(data=x1e, title="Residues", ylabel="$x_1e$")
 ```