Check out this snippet from Family Circle magazine (January, 2009, Liz Plosser): "Motorists who talk on a cell phone while driving are 9% slower to hit the brakes, 19% slower to resume normal speed after braking and four times more likely to crash."
Interesting, eh? Need more information? Sorry, that's all the information this article provided. So, what can we conclude? How reliable are these results? Can you believe what the author tells you? Why or why not?
Pretend you're a manager for one of the major cell phone service providers in the U.S. You've been asked by a major news magazine to speak to these "accusations." What would you say? Use your knowledge of "statistics for managers" to level some well-founded criticisms of the conclusions above.
Do not use personal opinions to battle statistics like these! Instead, explain why the numbers reported in Family Circle may, or may not, accurately represent the population of U.S. drivers.
Only provide a single idea, to get the conversation rolling.
Lack of experimental conditions (no controls over driving conditions)
When you cite that motorists are slower to hit brakes and slower to resume speed, what sample did you compare the phone calling group to? Were the road conditions identical? The cars? The age of the brakes? Where the other drivers on the road completing identical ...
Your tutorial is 211 and gives three potential statistical objections to the article's conclusions.