I have noticed that Yahoo has a trailing pe ratio of 26 for ATT yet other sites put it at around 15. Simply going by earnings 15ish seems correct so why does Yahoo and a few other sites have it at 25/26?
First; Do not rely on Yahoo's numbers; they are frequently wrong.
Second; Stocks don't trade relative to ttm EPS. They are priced relative to expected EPS which for 2013 are about $2.50 for a P/E of 13.6.
Third; T's average P/E has been 14.0, Average yield has been 4.6%.
Conclusion: T is a bargain.