How are ‘scores’, ‘predictions’ and ‘ probability’ calculated? How do you configure the system to understand when a relationship is looking poor? 

Predictive Scoring and Relationship Analytics are part of Sales Insights, an additional add-on capability to Dynamics to continuously analyse the vast collection of constituent-interaction data stored in Dynamics 365 (records) and Microsoft 365 (emails). This is to better understand business relationships, evaluate activities in relation to previous successes and choose the best path forward.  

Please go to https://docs.microsoft.com/en-us/dynamics365/ai/sales/overview to read more about Sales Insights.