I want to know how I can interpret variance when the sample sizes are not exact.

Here is my problem: I am analyzing daily playing data for poker players. For each player on each day their playing statistics are recorded. For each player I want to understand how consistent their playing stats are over time. My problem is that they play different numbers of hands each day (4000 one day, 5000 the next, and so on).

How can I control for # of hands played so that I can compare the consistency of different players? I cannot access the data in a fashion other than daily sums.

Thanks,

theyjamin