This file includes $30$ working days records $of$ a technical help center. $10$ employees answer calls for customers having technical problems with hardware and software. Variables $in$ this data file are:

Day: Observation day, $1-30$

Employee: First name $of$ the employee observed

Customers: Number $of$ calls answered $by$ employee

Average daily customer rating: All customers receive a short survey immediately after the call. they were asked $to$ rate the service using a scale $of1-5(5$ being the highest satisfaction$).$

Use this information $to$ answer all questions.

What $is$ the maximum number $of$ customers Joe helped $in$ a single day $of$ observation?