Answer from cs61c-en (Lai, Siu Lun Chris 16529329) for Question 1
Since TLB stores the recently used translation, it takes advantage of temporal locality, so the miss rate is low. On the other hand, if there is a miss on TLB, the processor will go to L1 to look for the memory. However, it's likely that L1 will miss again. Considering the number of miss over the number of attemp to look for the memory, the TLB miss rate is far lower than L1 cache miss rate