You can actually check these things. Stock prices and the dates of Steve Jobss product announcements are matters of fact:
23 October 2001, introduction of original iPod: AAPL fell about 5 percent.
7 January 2002, Macworld Expo keynote: AAPL fell 4 percent.
7 January 2003, Macworld Expo keynote: AAPL fell slightly.
6 January 2004, Macworld Expo keynote, introduction of iPod Mini: AAPL fell slightly.
11 January 2005, Macworld Expo keynote: AAPL fell over 6 percent.
10 January 2006, Macworld Expo keynote: AAPL rose over 6 percent.
9 January 2007, Macworld Expo keynote, introduction of the iPhone, now seen as the biggest and most important product introduction in Apple, and perhaps industry, history: AAPL rose over 8 percent.
15 January 2008, Macworld Expo keynote, introduction of MacBook Air: AAPL fell over 5 percent.
9 June 2008, WWDC keynote, introduction of iPhone 3G: AAPL fell 2 percent
27 January 2010, introduction of original iPad: AAPL was up slightly on the day, but then dropped and kept dropping for days.
7 June 2010, introduction of iPhone 4 (last phone introduced by Jobs): AAPL fell slightly, then dropped 3 percent the next day.