diff --git a/exercises.mk b/exercises.mk
index f9d9cd8..ae68f24 100644
--- a/exercises.mk
+++ b/exercises.mk
@@ -27,7 +27,7 @@ watchsolutions :
 	while true; do ! make -q solutions && make solutions; sleep 0.5; done
 
 clean :
-	rm -f *~ *.aux *.log *.out
+	rm -f *~ *.aux *.log $(EXERCISES:.pdf=.out) $(SOLUTIONS:.pdf=.out)
 
 cleanup : clean
 	rm -f $(SOLUTIONS) $(EXERCISES)
diff --git a/likelihood/exercises/mlestd.out b/likelihood/exercises/mlestd.out
index 947a8cd..25fec42 100644
--- a/likelihood/exercises/mlestd.out
+++ b/likelihood/exercises/mlestd.out
@@ -1,11 +1,11 @@
 n=50
-                                mean 3.189
-                  standard deviation 1.953
-      likelihood: standard deviation 1.953
-  log-likelihood: standard deviation 1.953
+                                mean 3.468
+                  standard deviation 1.833
+      likelihood: standard deviation 1.833
+  log-likelihood: standard deviation 1.833
 
 n=1000
-                                mean 3.094
-                  standard deviation 1.995
+                                mean 2.993
+                  standard deviation 2.077
       likelihood: standard deviation 1.000
-  log-likelihood: standard deviation 1.995
+  log-likelihood: standard deviation 2.077
diff --git a/likelihood/exercises/mlestd.pdf b/likelihood/exercises/mlestd.pdf
index c321734..4732ba4 100644
Binary files a/likelihood/exercises/mlestd.pdf and b/likelihood/exercises/mlestd.pdf differ