In this homework, you are required to build a classification tool using KNN for the customer

churn data $($the Excel data file is available on Blackboard$).$ Your job is to use the classification

tool to identify whether the customer without the label is churn or loyal. Your classification tool

needs to be cross validated with $10$ folds before it is applied to customers without the label.

Requirements:

$(1)$ You need to pre$-$process your data to make sure no missing values or errors in your data.

$(2)$ When you build up your KNN classification tool using cross validation, try $k=1,2,3,4,5$

and record the accuracy with the following table:

$(3)$ Use the best KNN model identified in $(2)$ to classify the customers without the label. You

need to provide your classification results for all the customers without the label. Please

answer following questions:

Total number of customers without the label$=?$

Total number of customers without the label classified as "churn" $=?$

Total number of customers without the label classified as "loyal" $=?$