And when speaking of any of the indexes, those indexes and changes are not mere averages of the prices of the stocks in the index. In at least some of the indexes--notably the Dow--the different stock issues are weighted differently, based on the capitalization of the respective companies.

Which is to say that the Dow (for instance) is a mathematical monster, and it's futile to try to relate a given index level or given change to anything in the real world. You just have to take the figures given and relate them to what they have been.   

Up is usually thought of as good, because most people think of "going long", that is buying low and selling high. Others, of course, hope for the price of a stock to go down, perhaps because they think they can buy a good stock cheaper than it's worth, or maybe because in a particular case, at least, they have "gone short", sold the stock in the hope to buy it back cheaper.

Dave Oesterreich