Answer: The game with the lower mean of 3.25 to 3.75.
In either game, the expected mean of the dice would be 3.5. This can be found by adding all of the possible values and dividing that by 6.
1 + 2 + 3 + 4 + 5 + 6 = 21 / 6 = 3.5
Therefore, you are more likely to roll the lower mean than the higher mean, so you should pick that one.