i2c connection: Arduino 3.3V <-> Spark Core

Dear All,

I have an homemade arduino with a Atmega168-20PU (running at 3.3V) which I would like to connect via i2c to my Spark Core (as master).

This is the connection I understood I should do:

where the value of resistors “R” can be any between 1.5k and 10k (http://docs.spark.io/firmware/#communication-wire).

Is the connection correct and what is the suggested value for R?
Thank you,

@d82k, that is the correct configuration. A good resistor value is 4.7K ohms. Which device will be slave and which is master?

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Thank you @peekay123 for your answer.
The Spark will be the master.