what does the 'response time' figures of a TFT monitor mean?

e.g. (Tr+Tf) 9ms + 16ms.

Is the lower 'ms' better, please could someone explain what these specs mean.

Repsonse Time is the amount of time needed for an LCD pixel to reach its ‘on’ (rise) state and then back to ‘off’ (fall) again. The lower the response time the better the monitor will display fast moving graphics.

Thanks. Thats actually the spec of the TFT i ordered. Just didnt know what it meant.