small fixes

P0. Data preparation.ipynb

@@ -168,7 +168,7 @@
       "\n",
       "Average number of ratings per item is 59.453.\n",
       "\n",
-      "Data sparsity (% of missing entries) is 6.3047%.\n"
+      "Data sparsity (% of missing entries) is 93.6953%.\n"
      ]
     }
    ],
@@ -179,7 +179,7 @@
     "\n",
     "print(f'Average number of ratings per user is {round(ratings/users,4)}. \\n')\n",
     "print(f'Average number of ratings per item is {round(ratings/items,4)}.\\n')\n",
-    "print(f'Data sparsity (% of missing entries) is {round(100*ratings/(users*items),4)}%.')"
+    "print(f'Data sparsity (% of missing entries) is {round(100*(1-ratings/(users*items)),4)}%.')"
    ]
   },
   {