diff --git a/statistics/exercises/exercises02.tex b/statistics/exercises/exercises02.tex
index 82e2528..3b2d080 100644
--- a/statistics/exercises/exercises02.tex
+++ b/statistics/exercises/exercises02.tex
@@ -221,11 +221,11 @@ Den Zentralen Grenzwertsatz wollen wir uns im Folgenden veranschaulichen.
         clear spikes;
         % better:
         clear all
-        x = load( 'poisson.mat' );
+        x = load('poisson.mat');
         poissonspikes = x.spikes;
-        x = load( pifou.mat' );
+        x = load('pifou.mat');
         pifouspikes = x.spikes;
-        x = load( 'lifadapt.mat' );
+        x = load('lifadapt.mat');
         lifadaptspikes = x.spikes;
       \end{lstlisting}
     \end{solution}