WESTCHESTER COUNTY, N.Y. (TheStreet) -- The media is, by and large, telling us to buy the new iPhone, but stay clear of Apple (AAPL) stock in the wake of today's iPhone 5 launch.

They are basing their advice on historic price movements after iPhone launches. How vast is the sample size? You didn't really ask that, did you? Since 2007, there have been (count 'em) four iPhones.

No matter.

The New York Post writes with emblematic certainty. Its sub-headline echoes the headline: "Buy phone, not stock, Apple shares dip following gadget intros"Just in case you were slow on the uptake, it was repeated in the lead: "It's Apple-bobbing season. Investors are hoping for a share boost from the tech giant's much anticipated iPhone 5 unveiling today, despite a history of post-launch lulls in the stock price."

Soon we hear how: "Apple's stock has dipped in the first 30 days after every major product launch since in 2008." That means, of course, excluding the first iPhone. So, depending on your time frame, (mid-to-long term the stock ran skyward after all these launches) Apple's stock did alright after one iPhone launch, disappointing after three. Make one shift in the statistical sample, and, well, we're all even.

Look: from a larger perspective, stocks are anticipatory mechanisms. It makes some sense that they might run up before an exciting product launch, giving back a portion of the gains afterwards. But acting on hard and fast rules from such a small, fallible sample size of four is a one-way ticket to financial Palookaville.

At the time of publication, Fuchs had no positions in any of the stocks mentioned in this column.

Marek Fuchs was a stockbroker for Shearson Lehman Brothers and a money manager before becoming a journalist who wrote The New York Times' "County Lines" column for six years. He also did back-up beat coverage of The New York Knicks for the paper's Sports section for two seasons and covered other professional and collegiate sports. He has contributed frequently to many of the Times' other sections, including National, Metro, Escapes, Style, Real Estate, Arts & Leisure, Travel, Money & Business, Circuits and the Op-Ed Page.

For his "Business Press Maven" column on how business and finance are covered by the media, Fuchs was named best business journalist critic in the nation by the Talking Biz website at The University of North Carolina School of Journalism and Mass Communication. Fuchs is a frequent speaker on the business media, in venues ranging from National Public Radio to the annual conference of the Society of American Business Editors and Writers.

Fuchs appreciates your feedback; click here to send him an email.

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