Formula field that calculates average values based on same date and same name of agent

Hello,

How do we set up a Formula-Numeric field that calculates average of values based on same date and same name of agent?  For example, in the image below, I want to capture in the field "Weekly Quality Score" the average of all Daily Quality Score for Effective Date of 09/30/19 per agent. So, for the first 5 rows, the values under "Weekly Quality Score" should be the same 97.22%. 




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Ma. Isabel Gumanid
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