ArduinoUno <--> I2C <--> ATtiny85's

Projects Programming
1

I want to communicate between one ArduinoUno and a lot of ATtiny85's with I2C.
Every ATtiny85's does a reading, every 5 minutes, and stores the result in it's EEProm.
It will store a average result after every measurement.
Ones an hour the ArduinoUno comes by and asks for the result.
How do I program the communication between the ArduinoUno and the ATtiny?

Thanks!