Texas Instruments (NYSE:TXN) reported first-quarter earnings after the bell yesterday, and what a report it was.

Revenues increased an astounding 34% over last year's first quarter, while earnings per diluted share tripled. Trend-wise, things are also looking good for the Dallas-based chip maker. Revenue was up 6% over fourth-quarter 2003, and, while earnings were down 28% from that period, the drop was caused by a confluence of three factors: The fourth quarter's earnings were boosted by profits from a sale of Micron Technologies (NYSE:MU) stock and the recognition of a tax benefit, while first-quarter earnings were depressed by a higher tax rate than applied the previous quarter.

As a result, Texas Instruments is raising its earnings projections for the second quarter to $0.23 to $0.26 per share from March's prediction of $0.19 to $0.22.

Compare that with Intel's (NASDAQ:INTC) results, announced Tuesday, where both earnings and revenues were down from the fourth quarter, and you will see why Texas Instruments shares jumped 1.2% in after-hours trading following its report and Intel's shares slumped 1.5% after its report.

One other thing: You may have noticed that when Intel's report came out, apparently missing analysts' earnings target by a penny (though that "miss" is debatable), Texas Instruments' shares fell in tandem with Intel's. Now, I don't mean to rant here, but that kind of synchronicity really gets my goat. Just because two companies, X and Y, are in the same business, and Company X has a bad quarter (or is perceived to have had a bad quarter), that does not mean that Company Y is going to have a bad quarter, too.

Companies in the same field of business are generally competitors, after all. Logically, if one of them "wins," the other one is supposed to lose. So why do investors so often assume that, hey, Merrill Lynch (NYSE:MER) had a great quarter, so maybe I should buy some Goldman Sachs (NYSE:GS) before it reports -- they're both banks, right? Granted, sometimes the theory works out. And yes, both Merrill Lynch and Goldman Sachs made good money this quarter. But it does not always work out that way.

Take the cell-phone makers, for example. Just because Ericsson (NASDAQ:ERICY) returned from the dead in February did not mean that you should have gone out and boughtNokia (NYSE:NOK). And just because Intel missed its earnings does not mean that you should sell every chip maker in the investing universe.

That's why the good people at the stock exchanges give different companies different ticker symbols.

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Fool contributor Rich Smith owns no shares in any company mentioned in this article.