Excel has SumIf and CountIf, but no AverageIf. However, with a little array magic, you can get Excel to average values, conditionally.

Before LAMBDA was introduced to Excel, you'd need to know how to use VBA or macros to create your own function. However, today, Excel's LAMBDA tool lets you do this using familiar Excel language ...

Microsoft Excel's new dynamic array functions make complex calculations easier than ever before.