What do minute rates of Timer and Meter metrics indicate?

All (mean|1-min|5-minute|15-minute)-rate metrics indicate throughput; i.e., how many units of information (events) where processed per second.

Mean rate

Calculates the rate at which events have occurred since the meter was created. But that's not very useful because it doesn't represent what is happening right now.

Minute rates

Calculates the rate at which events have ocurred using a technique called Exponentially-weighted moving average (EWMA).

This rate has the same exponential decay factor as the fifteen-minute load average in the top Unix command.

More Information

Take a look at the source code of Timer.java, Meter.java and EWMA.java

If you have more time, take a look at a talk about the topic by Coda Hale: Metrics, Metrics, Everywhere - Coda Hale