diff --git a/unit04_model_sel/prob/prob_model_sel.pdf b/unit04_model_sel/prob/prob_model_sel.pdf
index e4f7b49..84c1fd9 100644
Binary files a/unit04_model_sel/prob/prob_model_sel.pdf and b/unit04_model_sel/prob/prob_model_sel.pdf differ
diff --git a/unit04_model_sel/prob/prob_model_sel.tex b/unit04_model_sel/prob/prob_model_sel.tex
index 93a2522..5f51d01 100644
--- a/unit04_model_sel/prob/prob_model_sel.tex
+++ b/unit04_model_sel/prob/prob_model_sel.tex
@@ -268,7 +268,7 @@
 \[
     \mathrm{Bias}(x) := \Exp(f(x,\widehat{\beta})) -  f(x,\beta_0),
 \]
-as a function of the test point $x$, true parameter $\beta_0$ and test data $x_i$.
+as a function of the test point $x$, true parameter $\beta_0$ and training data $x_i$.
 \begin{enumerate}[(a)]
 \item The training data has no noise: $y_i = f(x_i,\beta_0)$.