JKISeason3-24_​sryu

<p><strong>Performing Cohort Analysis for a Business</strong></p><p><strong>Challenge 24</strong></p><p><br><strong>Level: </strong>Medium<br><br><strong>Description: </strong>Your company wants to perform a <strong>cohort analysis</strong> to find customers that started purchasing goods on the same month (cohorts), and then track their persistence over time. To solve this challenge, you must explore a transactions dataset from 2016, identify its cohorts, calculate the <em>customer retention ratio</em>, separate the purchases month by month, and then visualize the persistence of the cohorts over time. <strong>Note:</strong> <em>Customer retention rate</em> (CRR) is<strong> </strong>the percentage of customers a company retains over a period of time. If <em>E</em> is the number of customers at the end of 2016, <em>N</em> is the number of new customers during the period, and <em>S</em> is the number of customers in the beginning of 2016, then <em>CRR = [(E - N) / S] * 100</em>.</p>