Two data sets, P and Q, each consist of 5 integers and are summarized in the histograms shown. For each histogram, the first interval represents the frequency of integers greater than or equal to 0 but less than 10, the second interval represents the frequency of integers greater than or equal to 10 but less than 20, and so on.

Data Set P:
Interval [0,10): Frequency 2
Interval [10,20): Frequency 3

Data Set Q:
Interval [10,20): Frequency 2
Interval [20,30): Frequency 3

What is the smallest possible difference between the mean of data set Q and the mean of data set P?