diff --git a/examples/notebooks/top_12_german_companies/top_12_german_companies.ipynb b/examples/notebooks/top_12_german_companies/top_12_german_companies.ipynb
index 2e9b43c829..5507f52e75 100644
--- a/examples/notebooks/top_12_german_companies/top_12_german_companies.ipynb
+++ b/examples/notebooks/top_12_german_companies/top_12_german_companies.ipynb
@@ -6552,10 +6552,10 @@
    "source": [
     "// Group data by sector to compute average and standard deviations of ROA and ROE\n",
     "val roeAndRoaDf = companiesDf.groupBy { sector }.aggregate {\n",
-    "    ROA.mean() into \"Avg ROA\"\n",
-    "    ROA.std() into \"Std ROA\"\n",
-    "    ROE.mean() into \"Avg ROE\"\n",
-    "    ROE.std() into \"Std ROE\"\n",
+    "    (ROA.map { it.toString().replace(\".\", \"\").toDouble() }).mean() into \"Avg ROA\"\n",
+    "    (ROA.map { it.toString().replace(\".\", \"\").toDouble() }).std() into \"Std ROA\"\n",
+    "    (ROE.map { it.toString().replace(\".\", \"\").toDouble() }).mean() into \"Avg ROE\"\n",
+    "    (ROE.map { it.toString().replace(\".\", \"\").toDouble() }).std() into \"Std ROE\"\n",
     "}\n",
     "\n",
     "roeAndRoaDf"