Apple Inc (AAPL.O), the largest U.S. company by market value, will join the storied Dow Jones industrial average (.DJI), replacing AT&T Inc (T.N), in a change that reflects the dominant position of iPhone maker in the U.S. economy and society. The decision to nudge aside AT&T, which has been part of the Dow for the better part of a century, is a recognition of the way in which communications and technology have evolved over the last several decades.