How to calculate the miss ratio of a cache
Yes. The hit ratio is the fraction of accesses which are a hit. The miss ratio is the fraction of accesses which are a miss. It holds that
$$ \text{miss rate} = 1-\text{hit rate}.$$

The (hit/miss) latency (AKA access time) is the time it takes to fetch the data in case of a hit/miss.
If the access was a hit - this time is rather short because the data is already in the cache. But if it was a miss - that time is much linger as the (slow) L3 memory needs to be accessed.
The latency depends on the specification of your machine: the speed of the cache, the speed of the slow memory, etc.