[{'role': 'system', 'content': "You are an expert in machine learning and your task is to classify code snippets into one of the following categories: ['helper_functions', 'load_data', 'data_exploration', 'data_preprocessing', 'evaluation', 'modelling', 'prediction', 'result_visualization', 'save_results', 'comment_only']."}, {'role': 'user', 'content': 'Identify the single most appropriate category to which the provided code belongs. Provide your response as a single category label without any additional information, commentary, or personal opinions.\\nPython Code:mediaA_t1 = []\nfor i in range(10000):\nmediaA_t1.append(np.mean(np.random.choice(resultados_A.delta_t1,size = 100)))\nx_barra = pd.Series(mediaA_t1)\nplt.hist(x_barra, bins = 20, normed = 1)'}, {'role': 'assistant', 'content': 'data_exploration'}]