Um, "TZA" attempts to return 3X the move of the Russell 2000 on any given day, not the DJIA.

As an aside, for all these "2X" and "3X" ETF's/ETN's: DO NOT HOLD THEM FOR MORE THAN A DAY. 

The internal construction of these leveraged ETF's results in rapid time decay loss vs. the underlying issue. They attempt to return their 2X or 3X move of a single day's move - ie, the day you buy these. If you hold them longer than a day, you start losing.