Merge pull request #145 from JonathanTaws/patch-1

Added explicit feature pairs in explanation for feature correlation

Author: djarpin

introduction_to_applying_machine_learning/xgboost_customer_churn/xgboost_customer_churn.ipynb

@@ -243,7 +243,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "We see several features that essentially have 100% correlation with one another.  Including these feature pairs in some machine learning algorithms can create catastrophic problems, while in others it will only introduce minor redundancy and bias.  Let's remove them anyway."
+    "We see several features that essentially have 100% correlation with one another.  Including these feature pairs in some machine learning algorithms can create catastrophic problems, while in others it will only introduce minor redundancy and bias.  Let's remove one feature from each of the highly correlated pairs: Day Charge from the pair with Day Mins, Night Charge from the pair with Night Mins, Intl Charge from the pair with Intl Mins:"
    ]
   },
   {