diff --git a/cal_mean_variance.ipynb b/cal_mean_variance.ipynb
index a9070c5..c86863d 100644
--- a/cal_mean_variance.ipynb
+++ b/cal_mean_variance.ipynb
@@ -10,6 +10,7 @@
     "import sys\n",
     "import os\n",
     "from os.path import join as pjoin\n",
+    "from tqdm import tqdm\n",
     "\n",
     "\n",
     "# root_rot_velocity (B, seq_len, 1)\n",
@@ -23,7 +24,7 @@
     "    file_list = os.listdir(data_dir)\n",
     "    data_list = []\n",
     "\n",
-    "    for file in file_list:\n",
+    "    for file in tqdm(file_list, desc='reading files'):\n",
     "        data = np.load(pjoin(data_dir, file))\n",
     "        if np.isnan(data).any():\n",
     "            print(file)\n",