Stating falsehoods as if they are absolutely true is another fun way to play with the audience during a public speaking engagement. However, you must make the statements obviously false by your words and your facial expressions. When you use this technique in this fashion, you don't want to leave any doubt in the audience's mind whether you are being funny or not.
Deadpan expression, or keeping a straight face, is a good technique to couple with fake facts and statistics. Also, you should really, really sound like you are trying to convince the audience that what your saying is true. This overemphasis on the sound of truth also tells the audience you are lying.
One time I was doing a Secretaries Day function. I used an extremely serious voice when I told them that scientific studies had been conducted indicating that the only reason executives became executives was because they couldn't make it as secretaries. They loved it.
Another good technique to build up your joke is to use official sounding sources for the information. 'A study done for the Alaskan Pipeline Workers Union indicated that 97.2 percent of Alaskan Pipeline Workers wear No Nonsense panty hose.' When using this type of humor use 'exact numbers' which add an extra comic emphasis.